OptionalcurrentOptionalgetLive accessor for the precise media time at the moment the marker
is added. Preferred over currentTime because the cached state
lags behind a click-seek and is typically rounded — using it
causes the marker to land at the integer-second grid instead of
exactly where the user clicked.
OptionalmarkersOptionalonOptionalonOptionalon
Cached playhead position used for read-only display (e.g. fallback when
getCurrentTimeis not supplied). Note that consumers often round this to whole seconds for re-render budget — it's not a precise enough value to anchor a marker to a click position.