pub const fn select_participant_window(
current: CapacityCounter,
) -> ParticipantWindowCommitExpand description
Admits one entry into a per-participant retention window.
A window with headroom takes the entry and grows by one. A full window displaces its oldest member and stays exactly full. The entry ALWAYS lands: this selector has no refusal arm, which is the whole of Tom’s governing sentence — no configured number refuses an honest arrival — expressed in the type.