| AlwaysOnHotwordDetector | A class that lets a VoiceInteractionService implementation interact with always-on keyphrase detection APIs. | 
| AlwaysOnHotwordDetector.Callback | Callbacks for always-on hotword detection. | 
| AlwaysOnHotwordDetector.EventPayload | Additional payload for onDetected(AlwaysOnHotwordDetector.EventPayload). | 
| VoiceInteractionService | Top-level service of the current global voice interactor, which is providing support for hotwording etc. | 
| VoiceInteractionSession | An active interaction session, started by a VoiceInteractionService. | 
| VoiceInteractionSessionService | An active voice interaction session, initiated by a VoiceInteractionService. | 
