[Feature Request] Implement Non-blocking TLS connections (CA-272)

[txf-]

Is your feature request related to an issue you've encountered? If so, please elaborate. Currently, with blocking connections achieving a reasonable timeout is fairly difficult for TLS receive operations. with a long timeout connections maintain better stability, however if there are no data to receive, any other operation is blocked from transmitting while esp_tls_conn_read() is blocked. If the timeout is reduced, there are issues maintaining connection stability and the connection is often dropped.

Describe the new feature request I would like non-blocking mode to be implemented in "network_transport.c" of the coreMQTT Port.

Describe other alternatives you've considered I've tried this solution suggested in the freeRTOS forums

I configured it to be non_block, however it never seems to finish handshaking, regardless of the timeout. I've seen someone mention that non-blocking mode of the ESP-TLS library is broken, but I can't find any other mention or bug report describing the problem.