Pacer may accept same packet serveral time for resending, packet may spend non-zero time in pacer queue. As a result packet can be resend several time within one rtt wasting bandwidth. Bug: None Change-Id: I753a5400b47d3804735e66e539a1b103916d0c94 Reviewed-on: https://webrtc-review.googlesource.com/c/106260 Reviewed-by: Erik Språng <sprang@webrtc.org> Commit-Queue: Danil Chapovalov <danilchap@webrtc.org> Cr-Commit-Position: refs/heads/master@{#25205}