feat(parquet): add async support for wasm targets

[HoKim98]

Which issue does this PR close?

• Closes AsyncFileWriter doesn't need to be Send #7612.

Rationale for this change

Why are you proposing this change? If this is already explained clearly in the issue then this section is not needed.
Explaining clearly why changes are proposed helps reviewers understand your changes and offer better suggestions for fixes.

This PR introduces BoxedFuture type alias to replace futures::future::BoxFuture.
It helps building on WebAssembly targets (e.g. wasm32-unknown-unknown, wasm32-wasip2).

The original codes are driven from: https://github.com/apache/opendal/blob/37efe24235388788b892f46e4101d59ecd37918c/core/src/raw/futures_util.rs#L43-L58

I think it's not an ultimate solution, because the API rework is in progress.
But I think it's useful for now.

What changes are included in this PR?

• Replace all parquet's futures::future::BoxFuture into BoxedFuture for WASM targets, which is thread-local.
• Replace all FutureExt::boxed calls into Box::pin to catch Send automatically

Are these changes tested?

All build steps below are passed on my local machine:

• cargo build --package parquet --target wasm32-unknown-unknown -p parquet --features async
• cargo build --package parquet --target wasm32-wasip1 -p parquet --features async
• cargo build --package parquet --target wasm32-wasip2 -p parquet --features async

The tests are not passed because:

• wasm32-unknown-unknown: getrandom is not supported
• wasm32-wasip1, wasm32-wasip2: tokio/fs is not supported yet

Are there any user-facing changes?

NONE

[alamb]

I think it's not an ultimate solution, because the API rework is in progress.

Thank you for this PR @HoKim98

One thing I have been pushing on is a "SansIO" type of API for the parquet readers, described here:

• Decouple IO and CPU operations in the Parquet Reader (push decoder) #7983

The idea is that with those APIs, you could use your own IO routines (aka not the AsyncRead traits).

We recently released a metadata parsing version here:

• https://docs.rs/parquet/latest/parquet/file/metadata/struct.ParquetMetaDataPushDecoder.html

This lets you decode ParquetMetadata with any IO (e.g this example):

use tokio::io::{AsyncRead, AsyncReadExt, AsyncSeek, AsyncSeekExt};
// This function decodes Parquet Metadata from anything that implements
// [`AsyncRead`] and [`AsyncSeek`] such as a tokio::fs::File
async fn decode_metadata(
  file_len: u64,
  mut async_source: impl AsyncRead + AsyncSeek + Unpin
) -> Result<ParquetMetaData, ParquetError> {
  // We need a ParquetMetaDataPushDecoder to decode the metadata.
  let mut decoder = ParquetMetaDataPushDecoder::try_new(file_len).unwrap();
  loop {
    match decoder.try_decode() {
       Ok(DecodeResult::Data(metadata)) => { return Ok(metadata); } // decode successful
       Ok(DecodeResult::NeedsData(ranges)) => {
          // The decoder needs more data
          //
          // In this example we use the AsyncRead and AsyncSeek traits to read the
          // required ranges from the async source.
          let mut data = Vec::with_capacity(ranges.len());
          for range in &ranges {
            let mut buffer = vec![0; (range.end - range.start) as usize];
            async_source.seek(std::io::SeekFrom::Start(range.start)).await?;
            async_source.read_exact(&mut buffer).await?;
            data.push(Bytes::from(buffer));
          }
          // Push the data into the decoder and try to decode again on the next iteration.
          decoder.push_ranges(ranges, data).unwrap();
       }
       Ok(DecodeResult::Finished) => { unreachable!("returned metadata in previous match arm") }
       Err(e) => return Err(e),
    }
  }
}

I also have code to do the same for the actual parquet decoder here:

• Implement Push Parquet Decoder #7997

If you are interested in that feature I will try and prioritize it more

[HoKim98]

Hello @alamb, thank you for great work!

One thing I have been pushing on is a "SansIO" type of API for the parquet readers, described here:

I'll try and take some feedbacks about building on WASM targets.