Peeking a UDPSocket?

[matthewrobertbell]

I can use peek on a TCPStream to see how many bytes are available to read. I use this to avoid blocking when calling read.

With UDPSocket, there doesn't seem to be a way to avoid blocking when using recv_from to read data into a buffer. I want something that either reads a UDP packet or immediately returns. Does this exist?

EDIT: recv and recv_from seem to be exactly the same. recv uses recv_from in its example.

[matthewrobertbell]

It seems like mio has peek/peek_from on UDPStream in master (0.7), but not in 0.6 which async-std uses. Link: https://tokio-rs.github.io/mio/doc/mio/net/struct.UdpSocket.html#method.peek_from

It was added here: tokio-rs/mio@2f688de

I am new to async-std, how would I go about updating mio or otherwise adding these methods? Are there stability guarantees that would affect this?

[matthewrobertbell]

It would also seem useful to either implement Stream for UdpSocket, or create a UdpStream, where each Item in the stream is a UDP packet.

[yoshuawuyts]

@matthewrobertbell we most definitely want to implement peek as it also exists in std::net::UdpSocket, but we've been blocked on the mio 0.7 release for this. Once it's released we'll upgrade, and implement the method accordingly.