Function check_video_encoder_contract 

pub fn check_video_encoder_contract<E, F>(
    make: F,
    frames: &[Frame],
) -> Conformance
where
    E: VideoEncoder,
    F: FnMut() -> E,

Verify a VideoEncoder against the session contract.

make builds a fresh encoder; frames are valid input for it, with timestamps on its clock. Checked:

• output_config is available before the first frame.
• Receiving lazily and eagerly yields the same packets (bytes, timestamps, random-access flags); every packet has a timestamp and the timestamps are exactly the frames’.
• ReceivePending is followed by a Ready; end_input is idempotent, EndOfStream stable, send after it refused.
• A frame on another clock is ProtocolViolation::ClockMismatch.