Function check_video_decoder_contract 

pub fn check_video_decoder_contract<D, F>(
    make: F,
    config: &CodecConfig,
    packets: &[Packet],
) -> Conformance
where
    D: VideoDecoder + Send + 'static,
    F: FnMut() -> D,

Verify a VideoDecoder against the session contract.

make builds a fresh decoder; config configures it; packets is a valid stream for it. Checked:

• Receiving lazily (only when the decoder says ReceivePending, then draining) and eagerly (after every packet) yields the same frames: timestamps, presentation flags and pixels.
• ReceivePending leaves the packet untaken and is followed by a Ready.
• end_input is idempotent, EndOfStream is stable, and send after end_input is ProtocolViolation::SendAfterEnd.
• A packet from another configuration epoch is ProtocolViolation::EpochMismatch.
• A frame and a mapping of it stay valid while the decoder decodes more, resets and is dropped; after reset the same packets decode to the same frames.
• Behind erase_video_decoder, a tripped stop is Cancelled, every call after it Finished, until reset.