The first action opens a one-shot window. Its deadline is fixed at first_action_time + 1 second; later actions join that window without moving the deadline. Once a batch is taken, the queue becomes idle and no new deadline exists until another action arrives.

There is no action-count or memory-capacity cutoff. A window is released only by its deadline or an explicit read/synchronization barrier; admitting more actions never rejects input or triggers an early batch.

Screenshot, screencast, and other read barriers call flush before reading rendered state. This immediately returns the current batch and cancels its old deadline. A later action starts a fresh window.

Compaction is deliberately semantic:

adjacent scrolls in the same scope become one ordered ScrollRun;
only the latest complete logical click in a scope is retained;
ordered/opaque actions are never discarded;
order between surviving action kinds and scopes is preserved.

A scroll run keeps every step instead of summing deltas. Applying each step in order preserves clamping, scroll snap, delta modes, and target changes. The host applies the whole returned batch and then performs derived work such as IntersectionObserver delivery, layout, and rendering once.

The crate is synchronous and uses caller-provided Instants. The Page/event loop remains responsible for arming one timer for next_deadline, executing ready batches, and flushing before capture barriers.

The generic scope should identify the smallest independently ordered input target (for example a page/document pair). Clicks are replaced only within the same scope, and scroll runs never cross scope boundaries.

Typical host flow is:

Call push. If the admission contains a ready batch, execute that older batch first.
Replace the Page timer with next_deadline, or cancel it when the result is None.
On timer wake, call take_due; execute the returned actions in order and commit derived rendering work once.
Before screenshot/screencast, call flush, execute the returned batch and its one derived-work commit, then capture.

All timestamps supplied to one queue must come from the same monotonic clock and be admitted in event-loop order.

Test layers

Unit tests pin every state transition, deadline edge, compaction rule, counter, cancellation, and high-volume behavior with a virtual clock.
Public API tests compile the crate as an external consumer, including owned scopes, non-Clone payloads, consuming batches, all mouse buttons, and scroll metadata.
Model tests compare the implementation with an independent flat reference compactor for all 9,331 mixed sequences up to five actions, plus a deterministic 1,000-action uninterrupted stream.
End-to-end host tests model Page execution, one observer/render commit per batch, screenshot and screencast barriers, stale timer wakes, late input, sustained high-volume input, and a real timer armed from next_deadline.