A subsystem is initialized from a SubsystemDescriptorWithProvider for a given subsystem (Session, Plane, Face, etc.) and provides an interface to interact with that given subsystem until it is Destroyed. After a subsystem is created, it can be Started or Stopped to turn on and off functionality and preserve performance. The base type for the subsystem only exposes this functionality; this class is designed to be a base class for derived classes that expose more functionality specific to a given subsystem.
*Note:* Initializing a second subsystem from the same subsystem descriptor will return a reference to the existing subsystem, because only one subsystem is currently allowed for a single subsystem provider.
| running | 子系统是否在运行。This returns true after Start has been called on the subsystem, and false after Stop is called. |
| Destroy | 销毁子系统的此实例。Also unloads all resources acquired during the initialization step. Call this when you no longer need this instance of a subsystem.Note: Once a subsystem is Destroyed, script can still hold a reference but calling a method on it will result in a NullArgumentException. |
| Start | 启动子系统的一个实例。实例启动后，表示此实例的子系统将处于活动状态并能够进行交互。 |
| Stop | 停止子系统的一个实例。Once the instance is stopped, the subsystem representing this instance is no longer active and should not consume CPU resources. |