Function report_refused_frames 

fn report_refused_frames(
    items: &[ParsedItem],
    seen: &mut u64,
    ctx: &ForwardCtx,
    report: &Reporter<'_>,
)

Report the control frames the decoder refused in one feed.

Called from both control pipes: one parser refusing a frame is one parser, and a helper wired into a single site would have left the other pipe as silent as neither was.

The counter takes every refusal; the impairment goes out once per direction and carries the count it went out with. seen is that direction’s running acknowledgement, and it is a caller’s local because the parser deliberately holds no reporting state - how often to say a thing is a property of the event stream, not of the framing.