MeterProvider modified to not do shutdown if user has already shut down

Author: cijothomas

opentelemetry-sdk/CHANGELOG.md

@@ -11,6 +11,9 @@
   external sources to be sent through OpenTelemetry.
   [#2105](https://github.com/open-telemetry/opentelemetry-rust/pull/2105)
 - Feature: `SimpleSpanProcessor::new` is now public [#2119](https://github.com/open-telemetry/opentelemetry-rust/pull/2119)
+- `MeterProvider` modified to not invoke shutdown on `Drop`, if user has already
+  called `shutdown()`.
+  [#2156](https://github.com/open-telemetry/opentelemetry-rust/pull/2156)
 
 ## v0.25.0
 

opentelemetry-sdk/src/metrics/meter_provider.rs

@@ -130,8 +130,12 @@ impl SdkMeterProviderInner {
 
 impl Drop for SdkMeterProviderInner {
     fn drop(&mut self) {
-        if let Err(err) = self.shutdown() {
-            global::handle_error(err);
+        // If user has already shutdown the provider manually by calling
+        // shutdown(), then we don't need to call shutdown again.
+        if !self.is_shutdown.load(Ordering::Relaxed) {
+            if let Err(err) = self.shutdown() {
+                global::handle_error(err);
+            }   
         }
     }
 }