Function push_needs_retry 

pub fn push_needs_retry(
    result: Result<(), DenoiserError>,
) -> Result<bool, Error>

Reads the result of a PlanarDenoiser::push call for the push-then-drain-then-retry loop that file_mode.rs and stream_mode.rs both use.

Ok(false) means the push landed. Ok(true) means the queue was full, so the caller should drain one output and push again.

Any error other than QueueFull is passed on rather than discarded.