Audio changes (#579)

* Explicitly expose AudioSwitchHandler

* Default prioritizing speaker over earpiece

+---
+"client-sdk-android": minor
+---
+
+Default prioritizing speaker over earpiece

+---
+"client-sdk-android": minor
+---
+
+Explicitly expose AudioSwitchHandler from Room for easier audio handling

 /*
- * Copyright 2023-2024 LiveKit, Inc.
+ * Copyright 2023-2025 LiveKit, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,7 +27,8 @@ import javax.inject.Inject
 import javax.inject.Singleton
 
 /**
- * An [AudioHandler] built on top of [AudioSwitch].
+ * An [AudioHandler] built on top of [AudioSwitch]. This handles things such as
+ * getting the audio focus as needed, as well as automatic audio output device management.
  *
  * The various settings should be set before connecting to a [Room] and [start] is called.
  */
@@ -222,8 +223,8 @@ constructor(private val context: Context) : AudioHandler {
             listOf(
                 AudioDevice.BluetoothHeadset::class.java,
                 AudioDevice.WiredHeadset::class.java,
-                AudioDevice.Earpiece::class.java,
                 AudioDevice.Speakerphone::class.java,
+                AudioDevice.Earpiece::class.java,
             )
         }
     }

@@ -26,10 +26,13 @@ import dagger.assisted.Assisted
 import dagger.assisted.AssistedFactory
 import dagger.assisted.AssistedInject
 import io.livekit.android.ConnectOptions
+import io.livekit.android.LiveKit
+import io.livekit.android.LiveKitOverrides
 import io.livekit.android.RoomOptions
 import io.livekit.android.Version
 import io.livekit.android.audio.AudioHandler
 import io.livekit.android.audio.AudioProcessingController
+import io.livekit.android.audio.AudioSwitchHandler
 import io.livekit.android.audio.AuthedAudioProcessingController
 import io.livekit.android.audio.CommunicationWorkaround
 import io.livekit.android.dagger.InjectionNames
@@ -77,6 +80,17 @@ constructor(
     private val defaultDispatcher: CoroutineDispatcher,
     @Named(InjectionNames.DISPATCHER_IO)
     private val ioDispatcher: CoroutineDispatcher,
+    /**
+     * The [AudioHandler] for setting up the audio as need.
+     *
+     * By default, this is an instance of [AudioSwitchHandler].
+     *
+     * This can be substituted for your own custom implementation through
+     * [LiveKitOverrides.audioOptions] when creating the room with [LiveKit.create].
+     *
+     * @see [audioSwitchHandler]
+     * @see [AudioSwitchHandler]
+     */
     val audioHandler: AudioHandler,
     private val closeableManager: CloseableManager,
     private val e2EEManagerFactory: E2EEManager.Factory,
@@ -272,6 +286,14 @@ constructor(
     val remoteParticipants: Map<Participant.Identity, RemoteParticipant>
         get() = mutableRemoteParticipants
 
+    /**
+     * A convenience getter for the audio handler as a [AudioSwitchHandler].
+     *
+     * Will return null if [audioHandler] is not a [AudioSwitchHandler].
+     */
+    val audioSwitchHandler: AudioSwitchHandler?
+        get() = audioHandler as? AudioSwitchHandler
+
     private var sidToIdentity = mutableMapOf<Participant.Sid, Participant.Identity>()
 
     private var mutableActiveSpeakers by flowDelegate(emptyList<Participant>())