loop forever (default) or play once and hold the last frame.
Optionalnextname of an animation to switch to when this one finishes.
Optionaloncalled when the animation completes a cycle (each loop, or once if loop: false).
A one-frame frame animation completes once its frame delay has elapsed when
played with loop: false or next; a looping one-frame animation does not
step, so it never calls onComplete.
Optionalonplayback rate multiplier (1 = authored speed).
Normalized options for a played animation, shared by the 2D Sprite frame-animation path and the 3D Mesh keyframe-animation path so both accept the same
setCurrentAnimation(name, …)second argument.