iPhone: UDP socket send error after waking up from background mode (thanks Joe Meade for the report)

[bennylp]

UDP sockets are reset by iOS when the app goes into background mode. PJLIB handles this by detecting the error when receive event is set and recreating the sockets accordingly. This feature was added by ticket #1107.

Unfortunately sometimes it's the sending operation that comes first after the app is woken up, and since the UDP socket is in a bad state, this will cause the sending operation to fail. This will cause errors similar to these:

17:35:40.120 stuntsx0x9de55  STUN error sending message: Broken pipe
17:35:40.120 stuntp0x33b920  Error sending STUN request: Broken pipe
17:35:40.121 stuntp0x33b920  Session failed because STUN Binding request failed: Broken pipe
17:35:40.121        icetp00  STUN binding request failed: Broken pipe
17:35:40.121 stuntsx0xa17b5  STUN error sending message: Broken pipe
17:35:40.122 stuntp0x33af00  Error sending STUN request: Broken pipe
17:35:40.122 stuntp0x33af00  Session failed because STUN Binding request failed: Broken pipe

This ticket will fix the sending error by recreating the UDP sockets if the sending operation fails after waking up from background mode.

[bennylp]

(In [3491]) Fixed #1225: iPhone: UDP socket send error after waking up from background mode (thanks Joe Meade for the report)