Last DTLS handshake packets may not be sent to the wire at all

Submitted by Daniel F

Link to original bug (#795166)

Description

Sometimes FreeStreamer does not send last DTLS handshake packets to the wire at all, and starts sending SRTP/SRTCP. However receiver is not able to decode them, because handshake was not completed. DTLS handshake retry also fails, at least this happened during my tests.

I found this when I tested WebRTC connection between GStreamer and FreeSwitch, but this may be a generic problem (not related to WebRTC).

Logs and more details are here:
https://pastebin.com/E7HiAfd7
https://lists.freedesktop.org/archives/gstreamer-devel/2018-April/067556.html

Version: 1.14.0