tokio::io

Function copy_bidirectional

Source 
pub async fn copy_bidirectional<A, B>(
    a: &mut A,
    b: &mut B,
) -> Result<(u64, u64)>
where
    A: AsyncRead + AsyncWrite + Unpin + ?Sized,
    B: AsyncRead + AsyncWrite + Unpin + ?Sized,
Available on crate feature io-util only.
Expand description

Copies data in both directions between a and b.

This function returns a future that will read from both streams, writing any data read to the opposing stream. This happens in both directions concurrently.

If an EOF is observed on one stream, shutdown() will be invoked on the other, and reading from that stream will stop. Copying of data in the other direction will continue.

The future will complete successfully once both directions of communication has been shut down. A direction is shut down when the reader reports EOF, at which point shutdown() is called on the corresponding writer. When finished, it will return a tuple of the number of bytes copied from a to b and the number of bytes copied from b to a, in that order.

It uses two 8 KB buffers for transferring bytes between a and b by default. To set your own buffers sizes use copy_bidirectional_with_sizes().

§Errors

The future will immediately return an error if any IO operation on a or b returns an error. Some data read from either stream may be lost (not written to the other stream) in this case.

§Return value

Returns a tuple of bytes copied a to b and bytes copied b to a.