Håvard Graff authored Jun 02, 2020 and Håvard Graff committed Jun 05, 2020

Some audio-codecs (like opus) uses DTX (Discontinuous transmission),
in the way that they simply stop sending audio-packets when there is
no audio detected.

The expectation is then that the codec will use its internal PLC (packet
loss concealment) to create packets in place of those missing.

This patch is reusing the timer already existing for RTX and lost-events,
scheduling a lost-timer for the next sequence-number based on the
inter-packet spacing.