chapter-changed
chapter-changed: ((chapterIndex: number,
chapter: DigitalChapter) => void) playback-completed
playback-completed: (() => void)
playback-started
playback-started: ((startTime: number) => void)
progress-changed
seek-completed
seek-completed: ((actualTime: number) => void)
seek-started
seek-started: ((targetTime: number) => void)