Represents current state of a [BehaviorTree] instance. This class is used by the LimboAI debugger for the serialization and deserialization of [BehaviorTree] instance data. Additionally, it can be used with [BehaviorTreeView] to visualize the current state of a [BehaviorTree] instance. It is meant to be utilized in custom in-game tools. Returns current state of the [param bt_instance] encoded as a [BehaviorTreeData], suitable for use with [BehaviorTreeView]. Behavior tree instance can be acquired with [method BTPlayer.get_bt_instance].