code: @Implementation
    protected int getConnectionState(BluetoothDevice device) {
      return connectedDevices.contains(device)
          ? BluetoothProfile.STATE_CONNECTED
          : BluetoothProfile.STATE_DISCONNECTED;
    }
docs: Overrides behavior of {@link getConnectionState}.
  
  @return {@code BluetoothProfile.STATE_CONNECTED} if the given device has been previously added
  by a call to {@link ShadowBluetoothHeadset#addConnectedDevice}, and {@code
  BluetoothProfile.STATE_DISCONNECTED} otherwise.