Tokio I/O impl for `FuturesAsyncRead`

[sameer]

Hello,

In 0.46.0 onwards, the read traits were removed from Reader and pushed into methods like into_futures_async_read and read. However, support for the Tokio I/O traits was lost in the process.

Is there any interest in supporting these with feature gating? For now I've been using async-compat to work around this.

[Xuanwo]

There is a plan to implement into_tokio_async_read() -> TokioAsyncReader. However, I am not confident that adding a feature gate at the Reader level is a good idea.

Since there is a workaround for this, how about we leave this issue open to collect more feedback?