From 8317a8c797321fbaa03dbc4a48ed9bc7e4190fb6 Mon Sep 17 00:00:00 2001
From: Lucio Franco <luciofranco14@gmail.com>
Date: Mon, 21 Oct 2019 15:04:20 -0400
Subject: [PATCH 1/3] fix(codec): Enforce encoders/decoders are `Sync`

Closes #81
---
 tonic/src/codec/decode.rs | 10 +++++-----
 tonic/src/codec/mod.rs    |  4 ++--
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/tonic/src/codec/decode.rs b/tonic/src/codec/decode.rs
index 413afdb45..ba3686818 100644
--- a/tonic/src/codec/decode.rs
+++ b/tonic/src/codec/decode.rs
@@ -19,7 +19,7 @@ const BUFFER_SIZE: usize = 8 * 1024;
 /// This will wrap some inner [`Body`] and [`Decoder`] and provide an interface
 /// to fetch the message stream and trailing metadata
 pub struct Streaming<T> {
-    decoder: Box<dyn Decoder<Item = T, Error = Status> + Send + 'static>,
+    decoder: Box<dyn Decoder<Item = T, Error = Status> + Sync + Send + 'static>,
     body: BoxBody,
     state: State,
     direction: Direction,
@@ -48,7 +48,7 @@ impl<T> Streaming<T> {
         B: Body + Send + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
-        D: Decoder<Item = T, Error = Status> + Send + 'static,
+        D: Decoder<Item = T, Error = Status> + Sync + Send + 'static,
     {
         Self::new(decoder, body, Direction::Response(status_code))
     }
@@ -58,7 +58,7 @@ impl<T> Streaming<T> {
         B: Body + Send + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
-        D: Decoder<Item = T, Error = Status> + Send + 'static,
+        D: Decoder<Item = T, Error = Status> + Sync + Send + 'static,
     {
         Self::new(decoder, body, Direction::EmptyResponse)
     }
@@ -68,7 +68,7 @@ impl<T> Streaming<T> {
         B: Body + Send + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
-        D: Decoder<Item = T, Error = Status> + Send + 'static,
+        D: Decoder<Item = T, Error = Status> + Sync + Send + 'static,
     {
         Self::new(decoder, body, Direction::Request)
     }
@@ -78,7 +78,7 @@ impl<T> Streaming<T> {
         B: Body + Send + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
-        D: Decoder<Item = T, Error = Status> + Send + 'static,
+        D: Decoder<Item = T, Error = Status> + Sync + Send + 'static,
     {
         Self {
             decoder: Box::new(decoder),
diff --git a/tonic/src/codec/mod.rs b/tonic/src/codec/mod.rs
index c32c729af..3f345fdfd 100644
--- a/tonic/src/codec/mod.rs
+++ b/tonic/src/codec/mod.rs
@@ -28,9 +28,9 @@ pub trait Codec {
     type Decode: Send + 'static;
 
     /// The encoder that can encode a message.
-    type Encoder: Encoder<Item = Self::Encode, Error = Status> + Send + 'static;
+    type Encoder: Encoder<Item = Self::Encode, Error = Status> + Sync + Send + 'static;
     /// The encoder that can decode a message.
-    type Decoder: Decoder<Item = Self::Decode, Error = Status> + Send + 'static;
+    type Decoder: Decoder<Item = Self::Decode, Error = Status> + Sync + Send + 'static;
 
     /// The content type of this codec.
     ///

From f17376d637ff75172d6f069bcf8d47f750729dc2 Mon Sep 17 00:00:00 2001
From: Lucio Franco <luciofranco14@gmail.com>
Date: Mon, 21 Oct 2019 20:00:29 -0400
Subject: [PATCH 2/3] add more sync bounds

---
 tonic-build/src/client.rs               |  4 ++--
 tonic-build/src/server.rs               |  4 ++--
 tonic-examples/src/routeguide/server.rs |  5 +++--
 tonic-interop/src/server.rs             |  5 +++--
 tonic/Cargo.toml                        |  3 +++
 tonic/src/body.rs                       | 10 +++++-----
 tonic/src/client/grpc.rs                | 20 ++++++++++----------
 tonic/src/codec/decode.rs               | 11 +++++++----
 tonic/src/codec/encode.rs               | 12 +++++++-----
 tonic/src/server/grpc.rs                | 19 ++++++++++---------
 10 files changed, 52 insertions(+), 41 deletions(-)

diff --git a/tonic-build/src/client.rs b/tonic-build/src/client.rs
index a5dec9d1f..3c01efcd3 100644
--- a/tonic-build/src/client.rs
+++ b/tonic-build/src/client.rs
@@ -133,7 +133,7 @@ fn generate_client_streaming(method: &Method, proto: &str, path: String) -> Toke
     quote! {
         pub async fn #ident<S>(&mut self, request: tonic::Request<S>)
             -> Result<tonic::Response<#response>, tonic::Status>
-            where S: Stream<Item = #request> + Send + 'static,
+            where S: Stream<Item = #request> + Sync + Send + 'static,
         {
            self.ready().await?;
            let codec = tonic::codec::ProstCodec::new();
@@ -151,7 +151,7 @@ fn generate_streaming(method: &Method, proto: &str, path: String) -> TokenStream
     quote! {
         pub async fn #ident<S>(&mut self, request: tonic::Request<S>)
             -> Result<tonic::Response<tonic::codec::Streaming<#response>>, tonic::Status>
-            where S: Stream<Item = #request> + Send + 'static,
+            where S: Stream<Item = #request> + Sync + Send + 'static,
         {
            self.ready().await?;
            let codec = tonic::codec::ProstCodec::new();
diff --git a/tonic-build/src/server.rs b/tonic-build/src/server.rs
index d19f45a7d..155c7f7d8 100644
--- a/tonic-build/src/server.rs
+++ b/tonic-build/src/server.rs
@@ -146,7 +146,7 @@ fn generate_trait_methods(service: &Service, proto_path: &str) -> TokenStream {
 
                 quote! {
                     #stream_doc
-                    type #stream: Stream<Item = Result<#res_message, tonic::Status>>  + Send + 'static;
+                    type #stream: Stream<Item = Result<#res_message, tonic::Status>> + Sync + Send + 'static;
 
                     #method_doc
                     async fn #name(&self, request: tonic::Request<#req_message>)
@@ -164,7 +164,7 @@ fn generate_trait_methods(service: &Service, proto_path: &str) -> TokenStream {
 
                 quote! {
                     #stream_doc
-                    type #stream: Stream<Item = Result<#res_message, tonic::Status>> + Send + 'static;
+                    type #stream: Stream<Item = Result<#res_message, tonic::Status>> + Sync + Send + 'static;
 
                     #method_doc
                     async fn #name(&self, request: tonic::Request<tonic::Streaming<#req_message>>)
diff --git a/tonic-examples/src/routeguide/server.rs b/tonic-examples/src/routeguide/server.rs
index 5732c52cc..99efcb7ec 100644
--- a/tonic-examples/src/routeguide/server.rs
+++ b/tonic-examples/src/routeguide/server.rs
@@ -108,7 +108,8 @@ impl server::RouteGuide for RouteGuide {
         Ok(Response::new(summary))
     }
 
-    type RouteChatStream = Pin<Box<dyn Stream<Item = Result<RouteNote, Status>> + Send + 'static>>;
+    type RouteChatStream =
+        Pin<Box<dyn Stream<Item = Result<RouteNote, Status>> + Sync + Send + 'static>>;
 
     async fn route_chat(
         &self,
@@ -138,7 +139,7 @@ impl server::RouteGuide for RouteGuide {
 
         Ok(Response::new(Box::pin(output)
             as Pin<
-                Box<dyn Stream<Item = Result<RouteNote, Status>> + Send + 'static>,
+                Box<dyn Stream<Item = Result<RouteNote, Status>> + Sync + Send + 'static>,
             >))
     }
 }
diff --git a/tonic-interop/src/server.rs b/tonic-interop/src/server.rs
index a0d9c7360..eda185da8 100644
--- a/tonic-interop/src/server.rs
+++ b/tonic-interop/src/server.rs
@@ -12,8 +12,9 @@ pub struct TestService;
 
 type Result<T> = std::result::Result<Response<T>, Status>;
 type Streaming<T> = Request<tonic::Streaming<T>>;
-type Stream<T> =
-    Pin<Box<dyn futures_core::Stream<Item = std::result::Result<T, Status>> + Send + 'static>>;
+type Stream<T> = Pin<
+    Box<dyn futures_core::Stream<Item = std::result::Result<T, Status>> + Sync + Send + 'static>,
+>;
 
 #[tonic::async_trait]
 impl pb::server::TestService for TestService {
diff --git a/tonic/Cargo.toml b/tonic/Cargo.toml
index 3cfe74d0f..25cd20342 100644
--- a/tonic/Cargo.toml
+++ b/tonic/Cargo.toml
@@ -75,6 +75,9 @@ openssl1 = { package = "openssl", version = "0.10", optional = true }
 # rustls
 tokio-rustls = { version = "=0.12.0-alpha.4", optional = true }
 
+[dev-dependencies]
+static_assertions = "1.0"
+
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]
diff --git a/tonic/src/body.rs b/tonic/src/body.rs
index 41930edab..9003619e5 100644
--- a/tonic/src/body.rs
+++ b/tonic/src/body.rs
@@ -15,7 +15,7 @@ use std::{
 pub(crate) type BytesBuf = <Bytes as IntoBuf>::Buf;
 
 /// A trait alias for [`http_body::Body`].
-pub trait Body: sealed::Sealed {
+pub trait Body: sealed::Sealed + Sync + Send {
     /// The body data type.
     type Data: Buf;
     /// The errors produced from the body.
@@ -45,7 +45,7 @@ pub trait Body: sealed::Sealed {
 
 impl<T> Body for T
 where
-    T: HttpBody,
+    T: HttpBody + Send + Sync + 'static,
     T::Error: Into<Error>,
 {
     type Data = T::Data;
@@ -83,7 +83,7 @@ mod sealed {
 
 /// A type erased http body.
 pub struct BoxBody {
-    inner: Pin<Box<dyn Body<Data = BytesBuf, Error = Status> + Send + 'static>>,
+    inner: Pin<Box<dyn Body<Data = BytesBuf, Error = Status> + Sync + Send + 'static>>,
 }
 
 struct MapBody<B>(B);
@@ -92,7 +92,7 @@ impl BoxBody {
     /// Create a new `BoxBody` mapping item and error to the default types.
     pub fn new<B>(inner: B) -> Self
     where
-        B: Body<Data = BytesBuf, Error = Status> + Send + 'static,
+        B: Body<Data = BytesBuf, Error = Status> + Sync + Send + 'static,
     {
         BoxBody {
             inner: Box::pin(inner),
@@ -102,7 +102,7 @@ impl BoxBody {
     /// Create a new `BoxBody` mapping item and error to the default types.
     pub fn map_from<B>(inner: B) -> Self
     where
-        B: Body + Send + 'static,
+        B: Body + Sync + Send + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
     {
diff --git a/tonic/src/client/grpc.rs b/tonic/src/client/grpc.rs
index 95712c50d..07ffac564 100644
--- a/tonic/src/client/grpc.rs
+++ b/tonic/src/client/grpc.rs
@@ -62,8 +62,8 @@ impl<T> Grpc<T> {
         <T::ResponseBody as HttpBody>::Error: Into<crate::Error>,
         <T::ResponseBody as HttpBody>::Data: Into<Bytes>,
         C: Codec<Encode = M1, Decode = M2>,
-        M1: Send + 'static,
-        M2: Send + 'static,
+        M1: Sync + Send + 'static,
+        M2: Sync + Send + 'static,
     {
         let request = request.map(|m| stream::once(future::ready(m)));
         self.client_streaming(request, path, codec).await
@@ -81,10 +81,10 @@ impl<T> Grpc<T> {
         T::ResponseBody: Body + HttpBody + Send + 'static,
         <T::ResponseBody as HttpBody>::Error: Into<crate::Error>,
         <T::ResponseBody as HttpBody>::Data: Into<Bytes>,
-        S: Stream<Item = M1> + Send + 'static,
+        S: Stream<Item = M1> + Sync + Send + 'static,
         C: Codec<Encode = M1, Decode = M2>,
-        M1: Send + 'static,
-        M2: Send + 'static,
+        M1: Sync + Send + 'static,
+        M2: Sync + Send + 'static,
     {
         let (mut parts, body) = self.streaming(request, path, codec).await?.into_parts();
 
@@ -115,8 +115,8 @@ impl<T> Grpc<T> {
         <T::ResponseBody as HttpBody>::Error: Into<crate::Error>,
         <T::ResponseBody as HttpBody>::Data: Into<Bytes>,
         C: Codec<Encode = M1, Decode = M2>,
-        M1: Send + 'static,
-        M2: Send + 'static,
+        M1: Sync + Send + 'static,
+        M2: Sync + Send + 'static,
     {
         let request = request.map(|m| stream::once(future::ready(m)));
         self.streaming(request, path, codec).await
@@ -134,10 +134,10 @@ impl<T> Grpc<T> {
         T::ResponseBody: Body + HttpBody + Send + 'static,
         <T::ResponseBody as HttpBody>::Data: Into<Bytes>,
         <T::ResponseBody as HttpBody>::Error: Into<crate::Error>,
-        S: Stream<Item = M1> + Send + 'static,
+        S: Stream<Item = M1> + Sync + Send + 'static,
         C: Codec<Encode = M1, Decode = M2>,
-        M1: Send + 'static,
-        M2: Send + 'static,
+        M1: Sync + Send + 'static,
+        M2: Sync + Send + 'static,
     {
         let mut parts = Parts::default();
         parts.path_and_query = Some(path);
diff --git a/tonic/src/codec/decode.rs b/tonic/src/codec/decode.rs
index ba3686818..391df1709 100644
--- a/tonic/src/codec/decode.rs
+++ b/tonic/src/codec/decode.rs
@@ -27,6 +27,9 @@ pub struct Streaming<T> {
     trailers: Option<MetadataMap>,
 }
 
+#[cfg(test)]
+static_assertions::assert_impl_all!(Streaming<()>: Send, Sync);
+
 impl<T> Unpin for Streaming<T> {}
 
 #[derive(Debug)]
@@ -45,7 +48,7 @@ enum Direction {
 impl<T> Streaming<T> {
     pub(crate) fn new_response<B, D>(decoder: D, body: B, status_code: StatusCode) -> Self
     where
-        B: Body + Send + 'static,
+        B: Body + Sync + Send + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
         D: Decoder<Item = T, Error = Status> + Sync + Send + 'static,
@@ -55,7 +58,7 @@ impl<T> Streaming<T> {
 
     pub(crate) fn new_empty<B, D>(decoder: D, body: B) -> Self
     where
-        B: Body + Send + 'static,
+        B: Body + Sync + Send + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
         D: Decoder<Item = T, Error = Status> + Sync + Send + 'static,
@@ -65,7 +68,7 @@ impl<T> Streaming<T> {
 
     pub(crate) fn new_request<B, D>(decoder: D, body: B) -> Self
     where
-        B: Body + Send + 'static,
+        B: Body + Sync + Send + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
         D: Decoder<Item = T, Error = Status> + Sync + Send + 'static,
@@ -75,7 +78,7 @@ impl<T> Streaming<T> {
 
     fn new<B, D>(decoder: D, body: B, direction: Direction) -> Self
     where
-        B: Body + Send + 'static,
+        B: Body + Sync + Send + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
         D: Decoder<Item = T, Error = Status> + Sync + Send + 'static,
diff --git a/tonic/src/codec/encode.rs b/tonic/src/codec/encode.rs
index 7d91b4b94..5a0f94b1d 100644
--- a/tonic/src/codec/encode.rs
+++ b/tonic/src/codec/encode.rs
@@ -16,8 +16,9 @@ pub(crate) fn encode_server<T, U>(
     source: U,
 ) -> EncodeBody<impl Stream<Item = Result<BytesBuf, Status>>>
 where
-    T: Encoder<Error = Status>,
-    U: Stream<Item = Result<T::Item, Status>>,
+    T: Encoder<Error = Status> + Send + Sync + 'static,
+    T::Item: Send + Sync,
+    U: Stream<Item = Result<T::Item, Status>> + Send + Sync + 'static,
 {
     let stream = encode(encoder, source).into_stream();
     EncodeBody::new_server(stream)
@@ -28,8 +29,9 @@ pub(crate) fn encode_client<T, U>(
     source: U,
 ) -> EncodeBody<impl Stream<Item = Result<BytesBuf, Status>>>
 where
-    T: Encoder<Error = Status>,
-    U: Stream<Item = T::Item>,
+    T: Encoder<Error = Status> + Send + Sync + 'static,
+    T::Item: Send + Sync,
+    U: Stream<Item = T::Item> + Send + Sync + 'static,
 {
     let stream = encode(encoder, source.map(|x| Ok(x))).into_stream();
     EncodeBody::new_client(stream)
@@ -88,7 +90,7 @@ pub(crate) struct EncodeBody<S> {
 
 impl<S> EncodeBody<S>
 where
-    S: Stream<Item = Result<crate::body::BytesBuf, Status>>,
+    S: Stream<Item = Result<crate::body::BytesBuf, Status>> + Send + Sync + 'static,
 {
     pub(crate) fn new_client(inner: S) -> Self {
         Self {
diff --git a/tonic/src/server/grpc.rs b/tonic/src/server/grpc.rs
index 3653c79b8..038284b67 100644
--- a/tonic/src/server/grpc.rs
+++ b/tonic/src/server/grpc.rs
@@ -26,6 +26,7 @@ pub struct Grpc<T> {
 impl<T> Grpc<T>
 where
     T: Codec,
+    T::Encode: Sync,
 {
     /// Creates a new gRPC client with the provided [`Codec`].
     pub fn new(codec: T) -> Self {
@@ -40,7 +41,7 @@ where
     ) -> http::Response<BoxBody>
     where
         S: UnaryService<T::Decode, Response = T::Encode>,
-        B: Body + Send + 'static,
+        B: Body + Sync + Send + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -70,8 +71,8 @@ where
     ) -> http::Response<BoxBody>
     where
         S: ServerStreamingService<T::Decode, Response = T::Encode>,
-        S::ResponseStream: Send + 'static,
-        B: Body + Send + 'static,
+        S::ResponseStream: Sync + Send + 'static,
+        B: Body + Sync + Send + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -95,7 +96,7 @@ where
     ) -> http::Response<BoxBody>
     where
         S: ClientStreamingService<T::Decode, Response = T::Encode>,
-        B: Body + Send + 'static,
+        B: Body + Sync + Send + 'static,
         B::Data: Into<Bytes> + Send + 'static,
         B::Error: Into<crate::Error> + Send + 'static,
     {
@@ -115,8 +116,8 @@ where
     ) -> http::Response<BoxBody>
     where
         S: StreamingService<T::Decode, Response = T::Encode> + Send,
-        S::ResponseStream: Send + 'static,
-        B: Body + Send + 'static,
+        S::ResponseStream: Sync + Send + 'static,
+        B: Body + Sync + Send + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -130,7 +131,7 @@ where
         request: http::Request<B>,
     ) -> Result<Request<T::Decode>, Status>
     where
-        B: Body + Send + 'static,
+        B: Body + Sync + Send + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -158,7 +159,7 @@ where
         request: http::Request<B>,
     ) -> Request<Streaming<T::Decode>>
     where
-        B: Body + Send + 'static,
+        B: Body + Sync + Send + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -170,7 +171,7 @@ where
         response: Result<crate::Response<B>, Status>,
     ) -> http::Response<BoxBody>
     where
-        B: TryStream<Ok = T::Encode, Error = Status> + Send + 'static,
+        B: TryStream<Ok = T::Encode, Error = Status> + Sync + Send + 'static,
     {
         match response {
             Ok(r) => {

From 5105ca68455e4ac42b2d985f9c18d79d1b0c6333 Mon Sep 17 00:00:00 2001
From: Lucio Franco <luciofranco14@gmail.com>
Date: Thu, 24 Oct 2019 10:53:08 -0400
Subject: [PATCH 3/3] Switch order of Send and Sync

---
 tonic-build/src/client.rs               |  4 ++--
 tonic-build/src/server.rs               |  4 ++--
 tonic-examples/src/routeguide/server.rs |  4 ++--
 tonic-interop/src/server.rs             |  2 +-
 tonic/Cargo.toml                        |  6 ++----
 tonic/src/body.rs                       |  8 ++++----
 tonic/src/client/grpc.rs                | 20 ++++++++++----------
 tonic/src/codec/decode.rs               | 24 ++++++++++++------------
 tonic/src/codec/mod.rs                  |  4 ++--
 tonic/src/server/grpc.rs                | 18 +++++++++---------
 10 files changed, 46 insertions(+), 48 deletions(-)

diff --git a/tonic-build/src/client.rs b/tonic-build/src/client.rs
index 346221aba..edeeb240f 100644
--- a/tonic-build/src/client.rs
+++ b/tonic-build/src/client.rs
@@ -133,7 +133,7 @@ fn generate_client_streaming(method: &Method, proto: &str, path: String) -> Toke
     quote! {
         pub async fn #ident<S>(&mut self, request: tonic::Request<S>)
             -> Result<tonic::Response<#response>, tonic::Status>
-            where S: Stream<Item = #request> + Sync + Send + 'static,
+            where S: Stream<Item = #request> + Send + Sync + 'static,
         {
            self.ready().await?;
            let codec = tonic::codec::ProstCodec::new();
@@ -151,7 +151,7 @@ fn generate_streaming(method: &Method, proto: &str, path: String) -> TokenStream
     quote! {
         pub async fn #ident<S>(&mut self, request: tonic::Request<S>)
             -> Result<tonic::Response<tonic::codec::Streaming<#response>>, tonic::Status>
-            where S: Stream<Item = #request> + Sync + Send + 'static,
+            where S: Stream<Item = #request> + Send + Sync + 'static,
         {
            self.ready().await?;
            let codec = tonic::codec::ProstCodec::new();
diff --git a/tonic-build/src/server.rs b/tonic-build/src/server.rs
index 7c03dcc24..9173bff4f 100644
--- a/tonic-build/src/server.rs
+++ b/tonic-build/src/server.rs
@@ -146,7 +146,7 @@ fn generate_trait_methods(service: &Service, proto_path: &str) -> TokenStream {
 
                 quote! {
                     #stream_doc
-                    type #stream: Stream<Item = Result<#res_message, tonic::Status>> + Sync + Send + 'static;
+                    type #stream: Stream<Item = Result<#res_message, tonic::Status>> + Send + Sync + 'static;
 
                     #method_doc
                     async fn #name(&self, request: tonic::Request<#req_message>)
@@ -164,7 +164,7 @@ fn generate_trait_methods(service: &Service, proto_path: &str) -> TokenStream {
 
                 quote! {
                     #stream_doc
-                    type #stream: Stream<Item = Result<#res_message, tonic::Status>> + Sync + Send + 'static;
+                    type #stream: Stream<Item = Result<#res_message, tonic::Status>> + Send + Sync + 'static;
 
                     #method_doc
                     async fn #name(&self, request: tonic::Request<tonic::Streaming<#req_message>>)
diff --git a/tonic-examples/src/routeguide/server.rs b/tonic-examples/src/routeguide/server.rs
index 99efcb7ec..f56064a51 100644
--- a/tonic-examples/src/routeguide/server.rs
+++ b/tonic-examples/src/routeguide/server.rs
@@ -109,7 +109,7 @@ impl server::RouteGuide for RouteGuide {
     }
 
     type RouteChatStream =
-        Pin<Box<dyn Stream<Item = Result<RouteNote, Status>> + Sync + Send + 'static>>;
+        Pin<Box<dyn Stream<Item = Result<RouteNote, Status>> + Send + Sync + 'static>>;
 
     async fn route_chat(
         &self,
@@ -139,7 +139,7 @@ impl server::RouteGuide for RouteGuide {
 
         Ok(Response::new(Box::pin(output)
             as Pin<
-                Box<dyn Stream<Item = Result<RouteNote, Status>> + Sync + Send + 'static>,
+                Box<dyn Stream<Item = Result<RouteNote, Status>> + Send + Sync + 'static>,
             >))
     }
 }
diff --git a/tonic-interop/src/server.rs b/tonic-interop/src/server.rs
index eda185da8..738441501 100644
--- a/tonic-interop/src/server.rs
+++ b/tonic-interop/src/server.rs
@@ -13,7 +13,7 @@ pub struct TestService;
 type Result<T> = std::result::Result<Response<T>, Status>;
 type Streaming<T> = Request<tonic::Streaming<T>>;
 type Stream<T> = Pin<
-    Box<dyn futures_core::Stream<Item = std::result::Result<T, Status>> + Sync + Send + 'static>,
+    Box<dyn futures_core::Stream<Item = std::result::Result<T, Status>> + Send + Sync + 'static>,
 >;
 
 #[tonic::async_trait]
diff --git a/tonic/Cargo.toml b/tonic/Cargo.toml
index d3a82ee23..662ef9fda 100644
--- a/tonic/Cargo.toml
+++ b/tonic/Cargo.toml
@@ -41,10 +41,6 @@ tls = []
 name = "bench_main"
 harness = false
 
-[dev-dependencies]
-rand = "0.7.2"
-criterion = "0.3"
-
 [dependencies]
 bytes = "0.4"
 futures-core-preview = "=0.3.0-alpha.19"
@@ -85,6 +81,8 @@ tokio-rustls = { version = "=0.12.0-alpha.4", optional = true }
 
 [dev-dependencies]
 static_assertions = "1.0"
+rand = "0.7.2"
+criterion = "0.3"
 
 [package.metadata.docs.rs]
 all-features = true
diff --git a/tonic/src/body.rs b/tonic/src/body.rs
index 9003619e5..ee0a662ad 100644
--- a/tonic/src/body.rs
+++ b/tonic/src/body.rs
@@ -15,7 +15,7 @@ use std::{
 pub(crate) type BytesBuf = <Bytes as IntoBuf>::Buf;
 
 /// A trait alias for [`http_body::Body`].
-pub trait Body: sealed::Sealed + Sync + Send {
+pub trait Body: sealed::Sealed + Send + Sync {
     /// The body data type.
     type Data: Buf;
     /// The errors produced from the body.
@@ -83,7 +83,7 @@ mod sealed {
 
 /// A type erased http body.
 pub struct BoxBody {
-    inner: Pin<Box<dyn Body<Data = BytesBuf, Error = Status> + Sync + Send + 'static>>,
+    inner: Pin<Box<dyn Body<Data = BytesBuf, Error = Status> + Send + Sync + 'static>>,
 }
 
 struct MapBody<B>(B);
@@ -92,7 +92,7 @@ impl BoxBody {
     /// Create a new `BoxBody` mapping item and error to the default types.
     pub fn new<B>(inner: B) -> Self
     where
-        B: Body<Data = BytesBuf, Error = Status> + Sync + Send + 'static,
+        B: Body<Data = BytesBuf, Error = Status> + Send + Sync + 'static,
     {
         BoxBody {
             inner: Box::pin(inner),
@@ -102,7 +102,7 @@ impl BoxBody {
     /// Create a new `BoxBody` mapping item and error to the default types.
     pub fn map_from<B>(inner: B) -> Self
     where
-        B: Body + Sync + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
     {
diff --git a/tonic/src/client/grpc.rs b/tonic/src/client/grpc.rs
index 07ffac564..9301f713f 100644
--- a/tonic/src/client/grpc.rs
+++ b/tonic/src/client/grpc.rs
@@ -62,8 +62,8 @@ impl<T> Grpc<T> {
         <T::ResponseBody as HttpBody>::Error: Into<crate::Error>,
         <T::ResponseBody as HttpBody>::Data: Into<Bytes>,
         C: Codec<Encode = M1, Decode = M2>,
-        M1: Sync + Send + 'static,
-        M2: Sync + Send + 'static,
+        M1: Send + Sync + 'static,
+        M2: Send + Sync + 'static,
     {
         let request = request.map(|m| stream::once(future::ready(m)));
         self.client_streaming(request, path, codec).await
@@ -81,10 +81,10 @@ impl<T> Grpc<T> {
         T::ResponseBody: Body + HttpBody + Send + 'static,
         <T::ResponseBody as HttpBody>::Error: Into<crate::Error>,
         <T::ResponseBody as HttpBody>::Data: Into<Bytes>,
-        S: Stream<Item = M1> + Sync + Send + 'static,
+        S: Stream<Item = M1> + Send + Sync + 'static,
         C: Codec<Encode = M1, Decode = M2>,
-        M1: Sync + Send + 'static,
-        M2: Sync + Send + 'static,
+        M1: Send + Sync + 'static,
+        M2: Send + Sync + 'static,
     {
         let (mut parts, body) = self.streaming(request, path, codec).await?.into_parts();
 
@@ -115,8 +115,8 @@ impl<T> Grpc<T> {
         <T::ResponseBody as HttpBody>::Error: Into<crate::Error>,
         <T::ResponseBody as HttpBody>::Data: Into<Bytes>,
         C: Codec<Encode = M1, Decode = M2>,
-        M1: Sync + Send + 'static,
-        M2: Sync + Send + 'static,
+        M1: Send + Sync + 'static,
+        M2: Send + Sync + 'static,
     {
         let request = request.map(|m| stream::once(future::ready(m)));
         self.streaming(request, path, codec).await
@@ -134,10 +134,10 @@ impl<T> Grpc<T> {
         T::ResponseBody: Body + HttpBody + Send + 'static,
         <T::ResponseBody as HttpBody>::Data: Into<Bytes>,
         <T::ResponseBody as HttpBody>::Error: Into<crate::Error>,
-        S: Stream<Item = M1> + Sync + Send + 'static,
+        S: Stream<Item = M1> + Send + Sync + 'static,
         C: Codec<Encode = M1, Decode = M2>,
-        M1: Sync + Send + 'static,
-        M2: Sync + Send + 'static,
+        M1: Send + Sync + 'static,
+        M2: Send + Sync + 'static,
     {
         let mut parts = Parts::default();
         parts.path_and_query = Some(path);
diff --git a/tonic/src/codec/decode.rs b/tonic/src/codec/decode.rs
index cd0d9b664..fba1ba281 100644
--- a/tonic/src/codec/decode.rs
+++ b/tonic/src/codec/decode.rs
@@ -19,7 +19,7 @@ const BUFFER_SIZE: usize = 8 * 1024;
 /// This will wrap some inner [`Body`] and [`Decoder`] and provide an interface
 /// to fetch the message stream and trailing metadata
 pub struct Streaming<T> {
-    decoder: Box<dyn Decoder<Item = T, Error = Status> + Sync + Send + 'static>,
+    decoder: Box<dyn Decoder<Item = T, Error = Status> + Send + Sync + 'static>,
     body: BoxBody,
     state: State,
     direction: Direction,
@@ -27,9 +27,6 @@ pub struct Streaming<T> {
     trailers: Option<MetadataMap>,
 }
 
-#[cfg(test)]
-static_assertions::assert_impl_all!(Streaming<()>: Send, Sync);
-
 impl<T> Unpin for Streaming<T> {}
 
 #[derive(Debug)]
@@ -48,40 +45,40 @@ enum Direction {
 impl<T> Streaming<T> {
     pub(crate) fn new_response<B, D>(decoder: D, body: B, status_code: StatusCode) -> Self
     where
-        B: Body + Sync + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
-        D: Decoder<Item = T, Error = Status> + Sync + Send + 'static,
+        D: Decoder<Item = T, Error = Status> + Send + Sync + 'static,
     {
         Self::new(decoder, body, Direction::Response(status_code))
     }
 
     pub(crate) fn new_empty<B, D>(decoder: D, body: B) -> Self
     where
-        B: Body + Sync + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
-        D: Decoder<Item = T, Error = Status> + Sync + Send + 'static,
+        D: Decoder<Item = T, Error = Status> + Send + Sync + 'static,
     {
         Self::new(decoder, body, Direction::EmptyResponse)
     }
 
     pub(crate) fn new_request<B, D>(decoder: D, body: B) -> Self
     where
-        B: Body + Sync + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
-        D: Decoder<Item = T, Error = Status> + Sync + Send + 'static,
+        D: Decoder<Item = T, Error = Status> + Send + Sync + 'static,
     {
         Self::new(decoder, body, Direction::Request)
     }
 
     fn new<B, D>(decoder: D, body: B, direction: Direction) -> Self
     where
-        B: Body + Sync + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
-        D: Decoder<Item = T, Error = Status> + Sync + Send + 'static,
+        D: Decoder<Item = T, Error = Status> + Send + Sync + 'static,
     {
         Self {
             decoder: Box::new(decoder),
@@ -294,3 +291,6 @@ impl<T> fmt::Debug for Streaming<T> {
         f.debug_struct("Streaming").finish()
     }
 }
+
+#[cfg(test)]
+static_assertions::assert_impl_all!(Streaming<()>: Send, Sync);
diff --git a/tonic/src/codec/mod.rs b/tonic/src/codec/mod.rs
index 3f345fdfd..d316a11a1 100644
--- a/tonic/src/codec/mod.rs
+++ b/tonic/src/codec/mod.rs
@@ -28,9 +28,9 @@ pub trait Codec {
     type Decode: Send + 'static;
 
     /// The encoder that can encode a message.
-    type Encoder: Encoder<Item = Self::Encode, Error = Status> + Sync + Send + 'static;
+    type Encoder: Encoder<Item = Self::Encode, Error = Status> + Send + Sync + 'static;
     /// The encoder that can decode a message.
-    type Decoder: Decoder<Item = Self::Decode, Error = Status> + Sync + Send + 'static;
+    type Decoder: Decoder<Item = Self::Decode, Error = Status> + Send + Sync + 'static;
 
     /// The content type of this codec.
     ///
diff --git a/tonic/src/server/grpc.rs b/tonic/src/server/grpc.rs
index 038284b67..5f9cabf91 100644
--- a/tonic/src/server/grpc.rs
+++ b/tonic/src/server/grpc.rs
@@ -41,7 +41,7 @@ where
     ) -> http::Response<BoxBody>
     where
         S: UnaryService<T::Decode, Response = T::Encode>,
-        B: Body + Sync + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -71,8 +71,8 @@ where
     ) -> http::Response<BoxBody>
     where
         S: ServerStreamingService<T::Decode, Response = T::Encode>,
-        S::ResponseStream: Sync + Send + 'static,
-        B: Body + Sync + Send + 'static,
+        S::ResponseStream: Send + Sync + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -96,7 +96,7 @@ where
     ) -> http::Response<BoxBody>
     where
         S: ClientStreamingService<T::Decode, Response = T::Encode>,
-        B: Body + Sync + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes> + Send + 'static,
         B::Error: Into<crate::Error> + Send + 'static,
     {
@@ -116,8 +116,8 @@ where
     ) -> http::Response<BoxBody>
     where
         S: StreamingService<T::Decode, Response = T::Encode> + Send,
-        S::ResponseStream: Sync + Send + 'static,
-        B: Body + Sync + Send + 'static,
+        S::ResponseStream: Send + Sync + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -131,7 +131,7 @@ where
         request: http::Request<B>,
     ) -> Result<Request<T::Decode>, Status>
     where
-        B: Body + Sync + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -159,7 +159,7 @@ where
         request: http::Request<B>,
     ) -> Request<Streaming<T::Decode>>
     where
-        B: Body + Sync + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -171,7 +171,7 @@ where
         response: Result<crate::Response<B>, Status>,
     ) -> http::Response<BoxBody>
     where
-        B: TryStream<Ok = T::Encode, Error = Status> + Sync + Send + 'static,
+        B: TryStream<Ok = T::Encode, Error = Status> + Send + Sync + 'static,
     {
         match response {
             Ok(r) => {