* Handle multiple codecs in renegotiation
update pion to v3.1.9 for answer same order of codec as publisher.
register enable codecs in subscriber peerconnectin created.
add codec parameter to buffer.bind
buffer should use the codec of TrackRemote as it's codec mime.
sent h264blankframe when DownTrack closing
* Separate from ion-sfu
changes:
1. extract pkg/buffer, twcc, sfu, relay, stats, logger
2. to solve cycle import, move ion-sfu/pkg/logger to pkg/sfu/logger
3. replace pion/ion-sfu => ./
reason: will change import pion/ion-sfu/pkg/* to livekit-server/pkg/*
after this pr merged. Just not change any code in this pr, because it
will confused with the separate code from ion-sfu in review.
* Move code from ion-sfu to pkg/sfu
* fix build error for resovle conflict
Co-authored-by: cnderrauber <zengjie9004@gmail.com>