Dedicated enum instead of Ok(0) in read

[agluszak]

From the tutorial:

Handling EOF

When the read half of the TCP stream is shut down, a call to read() returns Ok(0). It is important to exit the read loop at this point. Forgetting to break from the read loop on EOF is a common source of bugs.

loop {
    match socket.read(&mut buf).await {
        // Return value of `Ok(0)` signifies that the remote has
        // closed
        Ok(0) => return,
        // ... other cases handled here
    }
}

Forgetting to break from the read loop usually results in a 100% CPU infinite loop situation. As the socket is closed, socket.read() returns immediately. The loop then repeats forever.

Wouldn't it be better if there was a dedicated enum?

enum BytesRead {
  EOF,
  Length(NonZeroUsize)
}

Then the EOF case would have to be handled explicitly

[Darksonn]

That's certainly a reasonable way to approach it, and I'm sure it has been suggested before, but we chose to keep it as an integer to mirror the standard library traits.