OptionalfillBreak duration in seconds. Required for fill and loop pacing;
ignored for hold.
OptionalmaxFor fill mode: if any scaled step would exceed this cap (in
seconds), fall back to loop mode with the original authored
durations instead.
OptionalpacingPacing mode. Defaults to 'hold' when absent.
Options that control how step durations relate to the break length. When omitted the function behaves as hold mode (back-compat).