Function report_shaping 

fn report_shaping(
    outcome: Option<ShapeReport>,
    shaped: Option<&ShapedStream>,
    ctx: &ForwardCtx,
    report: &Reporter<'_>,
)

Emit whatever a shaped release decided, if anything.

Nothing at all on an unshaped stream and on both control pipes: the queue only ever produces a report when a scheduler was installed on it.