Question: Why using Sample.duration to calculate rtp timestamp?

[tubzby]

https://github.com/webrtc-rs/rtp/blob/ee39d4ea79bd33c01b5b802abdffb183ef586416/src/packetizer/mod.rs#L137

https://github.com/webrtc-rs/webrtc/blob/4bb9614c56131accc47e903eed086b46c9a2e57c/webrtc/src/track/track_local/track_local_static_sample.rs#L137

For each Sample we do have a timestamp field, but to detect the duration we might need 2 samples in which 1 frame lag will be introduced.