rtpmanager: Google Transport-Wide Congestion Control RTP Extension
Generating and parsing the RTCP-messages described in: https://tools.ietf.org/html/draft-holmer-rmcat-transport-wide-cc-extensions-01
Generating and parsing the RTCP-messages described in: https://tools.ietf.org/html/draft-holmer-rmcat-transport-wide-cc-extensions-01