dispose

Disposes the checkpointer, stopping any timed checkpoint saving.

This is called when the associated document is released (see setDocument). The timed strategy schedules an Observable.interval whose subscription keeps the document (and its native counterpart) alive and keeps calling saveCheckpoint on it long after the document would otherwise be torn down; disposing stops that subscription and prevents further checkpoint saves.

Disposal is not permanent: it resets the strategy to MANUAL, so if the same document instance is re-used (for example after a configuration change) checkpointing resumes as soon as a strategy is set again via setStrategy. This method is idempotent.