Class TableViewportSubscription

This object serves as a "handle" to a subscription, allowing it to be acted on directly or canceled outright. If you retain an instance of this, you have two choices - either only use it to call close() on it to stop the table's viewport without creating a new one, or listen directly to this object instead of the table for data events, and always call close() when finished. Calling any method on this object other than close() will result in it continuing to live on after setViewport is called on the original table, or after the table is modified.