Trailing debounce: quiet time after the last call before writing.
OptionalmaxCeiling on how long a continuous stream of calls may postpone the write, measured from the first call since the last write. Omitted = unbounded (pure trailing debounce).
OptionalleadingLeading edge: the first call after a quiet period (no save started for
delayMs) writes within this many ms, and later calls in the same window
cannot push that write back. Omitted = no leading edge.
Arguments of OPFSMetadataManager.scheduleSave.