Playback control for AnimationNodeStateMachine. Allows control of [AnimationTree] state machines created with [AnimationNodeStateMachine]. Retrieve with [code]$AnimationTree.get("parameters/playback")[/code]. [b]Example:[/b] [codeblock] var state_machine = $AnimationTree.get("parameters/playback") state_machine.travel("some_state") [/codeblock] Returns the currently playing animation state. Returns [code]true[/code] if an animation is playing. Starts playing the given animation. Stops the currently playing animation. Transitions from the current state to another one, following the shortest path.