Before this CL, before sending out any chunk, all inflight data chunks
were inspected to find out if they were supposed to be retransmitted.
When the congestion window is large, this is a lot of data chunks to
inspect, which takes time.
By having a separate collection for chunks to be retransmitted, this
becomes a much faster operation. In most cases, constant in time.
Bug: webrtc:12799
Change-Id: I0d43ba7a88656eead26d5e0b9c4735622a8d080e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/219626
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34178}
7b4fd5ca59