avoid intermediate type RtcpStatistics, Instead write to rtcp::ReportBlock directly. Bug: webrtc:10678 Change-Id: Ia5f840d720e48d79cbbcb0c95cd221c87156205e Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/218840 Reviewed-by: Erik Språng <sprang@webrtc.org> Commit-Queue: Danil Chapovalov <danilchap@webrtc.org> Cr-Commit-Position: refs/heads/master@{#34021}