Provide a way to flush control messages

[singpolyma]

It would be nice if I could call sendPing and then call something that would do the normal "auto-handle control messages" logic (including the ConnectionClosed exception) without actually reading out the next data message.

[jaspervdj]

Hmm, I guess this makes sense. How would you use this in your application? Should it just block and return () when a data message is received?

Alternatively, would a way of pushing back a data message on the stream also suffice?

[singpolyma]

Blocking and returning () is what I had in mind. A pushback mechanism would let me build this myself, if that fits better with the library goals.