Define RTCP XR configuration structure.
Add functions to configure RTCP XR packet sending intervals.
Send RTCP XR packets according to the set intervals.
Set flags in RTCP XR stat summary packet.
Notify sending of RTCP XR packets.
Add RTCP XR accessor.
Perform msgpullup on sent RTCP packet.
Define accessors for content of RTCP XR packets.
Send RTCP XR dlrr packet when receiving a RTCP XR rcvr-rtt packet.