Session sending message timeout

[babaev]

Currently session sends queued messages only after receiving incoming message or sessionEvent.
https://github.com/quickfixgo/quickfix/blob/master/session.go#L527
Is it possible to remove this timeout by firing something like "needSend" event or by changing toSend queue to channel logic?

[cbusbey]

Hi @babaev. So originally this was queuing logic, but you could end up in a deadlock if on fromApp or fromAdmin the caller sends a message and blocks waiting for that message to be processed. So that's why we have the queuing logic you see now.

I think you are on to something with the "needSend" event and would be a great enhancement to prevent the delayed send as you have described. This contribution would be very welcome.

[cbusbey]

Ref #84