2.2.2 Media Event Callback

The extender device uses this service to respond to out-of-band errors that the device has encountered or for end-of-stream states that aid in support of the three-box model. Errors include device subsystem failures (decoder errors), Digital Rights Management (DRM) errors, and so on. The extender device has a proxy code to send messages to the host while the host has a stub to receive messages.