Document that UdpSocket::recv and recv_from do not read from the buffer

[dtolnay]

fn recv(&self, buf: &mut [u8]) -> Result<usize>;
fn recv_from(&self, buf: &mut [u8]) -> Result<(usize, SocketAddr)>;

It is important for these to document that they only write to the buffer, not read from it, because that means it is safe to pass an uninitialized buffer. It would be wasteful to construct a buffer, initialize it to contain all 0 bytes, and pass it to UdpSocket.

[frehberg]

And add to the docs, if recv returns with Ok(N), the following code must not iterate over complete array, but iterate over a slice of the array buf[0,..,N-1].

[frehberg]

can be closed?

[dtolnay]

I don't think so. The docs in mio still need some work.

https://github.com/carllerche/mio/blob/5b9d20c4e01a63115ebdb6b87970fc9dd361a29b/src/net/udp.rs#L79-L81

[frehberg]

Finally the patch has been rebased, and could be merged

[carllerche]

The original PR got messed up somehow. I moved the commit to #775.

[carllerche]

Thanks. This has been merged (f6f293f).