The sequences of threads entering the VideoStreamEncoder has been
unclear. Fix this by renaming the uninformational |main_queue_| to
|worker_queue_|, and introduce a new |network_queue_| which is set
on construction.
Bug: chromium:1255737
Change-Id: Ic4d3a5b8188b8cc98e60b72aee2c09c9afbc7356
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/236523
Reviewed-by: Henrik Andreassson <henrika@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Markus Handell <handellm@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35283}