Add zero capacity bounded channel

[bnyu]

A difference between zero capacity and one capacity bounded channel is that call try_send() return OK only when there is already receiver wait on it. And this is useful is somecase.

Golang and crossbeam-channel both have zero capacity bounded channel, maybe we should support it.

[notgull]

Adding a rendezvous channel inside of the current implementation would add some level of complexity to the implementation. I'd like to avoid that if necessary.

I'd be happy to add rendezvous channel functionality to this crate, but I'd have to see the implementation first.

[al8n]

Hi @notgull, anyone works on this? If not, I would like to give it a try.

[notgull]

Hi @notgull, anyone works on this? If not, I would like to give it a try.

Sure, go ahead!