Different RecvError::Finished behavior for embassy-net tcp recv() vs recv_with()

[mattiasgronlund]

Hi,

Is there a reason for the difference regarding Err(tcp::RecvError::Finished) for tcp.rs read_with(...):

Poll::Ready(match s.recv(unwrap!(f.take())) {
    // Connection reset. TODO: this can also be timeouts etc, investigate.
    Err(tcp::RecvError::Finished) | Err(tcp::RecvError::InvalidState) => {
        Err(Error::ConnectionReset)
    }
    Ok(r) => Ok(r),
})

and tcp.rs read(...):

    ...
    // EOF
    Err(tcp::RecvError::Finished) => Poll::Ready(Ok(0)),
    // Connection reset. TODO: this can also be timeouts etc, investigate.
    Err(tcp::RecvError::InvalidState) => Poll::Ready(Err(Error::ConnectionReset)),

Might it be so that, Err(tcp::RecvError::Finished) indicates when other end has closed it's write side, i.e. EOF, which read() indicates, but read_recv() should not distinguish between other end closed its write side and a ConnectionReset)?

I suppose read() does the right thing, even if it feels a bit error prone to indicate a non recoverable EOF with Ok(0) instead of ConnectionReset (I suppose I am not the only who managed forget the Ok(0) case and locked up my task in a tight loop).

In any case, thanks for the impressive work put into embassy-rs!

BR
Mattias