feature request: receive with timeout

[rwbarton]

I'd like to be able to do a receive with a timeout, so something like

receiveWithTimeout :: Protocol p => Int -> WebSockets p (Maybe (Message p))

As far as I can tell this isn't possible with the current API, please correct me if I am wrong!

I realize this might be a little tricky: what if we have received part of a frame when the timeout occurs?

For my specific application I think I can cook up a funny workaround, so this feature isn't critical to me. But the code would be much more natural with a receive-with-timeout.

[rwbarton]

Upon further reflection I should be able to just have the WebSockets thread feed all incoming data into a Chan and have a separate, ordinary IO thread read from that with timeout and readChan and do its writing using the Sink mechanism.