Sendmsg Thread Blocking

[wsxjbupt]

Describe the bug
Sendmsg Thread Blocking

Expected behavior
normal running.

Actual Behavior
Use the pair_0 protocol for communication, Occasional Sendmsg Thread Block on function nng_aio_wait，Check the call stack information. Everything is normal, pair0_sock->wmq is full, sendmsg thread block on funciton nng_aio_wait，all nng_task is idle.
After receiving the message from the peer end, everything returns to normal.

To Reproduce
If possible include actual reproduction test code here.
Minimal C test cases are perferred.

** Environment Details **

• 1.5.2
• aarch64
• open euler
• shared lib

Additional context
Add any other context about the problem here.

[gdamore]

Pair blocks if there is no receiver. That's by design.

If you want to fail the send instead, use nng_aio_set_timeout() to set a short timeout.

[gdamore]

It also blocks due to backpressure.

If you want a non-blocking (but will lose messages if receiver cannot keep up) pattern, check out PUB/SUB.

[gdamore]

I'm closing this because there isn't a bug.