<summary> Removes the registered instance from the dictionary. </summary>
<summary> Retrieve the living instance if there is one, or null if not. </summary> <returns>The instance if it is alive, or null if there is none.</returns>
<summary> Retrieve or create an instance for the native handle. </summary> <returns>The instance, or null if the handle was null.</returns>
<summary> Registers the specified instance with the dictionary. </summary>