Implement functions similar to write_message and read_message from tungstenite

[lescuer97]

Hi i don't know if is yet to be implemented or not going to be, but the functions to comunicate with the web socket i think are really important, i would be glad to do it, but a little help would be great because I'm kind of novice hahahaha, i think this is is necesary because i haven't seen a way in this package for complicating with the WebSocket, if i'm wrong please correct me ;).

[daniel-abramov]

We have not planned it, because you can get the same functionality by calling the appropriate functions on the Stream and Sink. It would be possible to add a wrapper to be able to read and write a single message. Not sure if it would be very useful for normal usage though...