copy method
Creates a copy of a track, largely so that the stream knows it's mutated
Implementation
NowPlayingTrack copy() => NowPlayingTrack(
id: this.id,
title: this.title,
album: this.album,
artist: this.artist,
duration: this.duration,
position: this.position,
state: this.state,
source: this.source,
createdAt: this.createdAt,
);