GattRequestRejectedException   
    Thrown on Android when underlying android.bluetooth.BluetoothDevice method call returns false. This can occur under the following conditions:
- Request isn't allowed (e.g. reading a non-readable characteristic) 
- Underlying service or client interface is missing or invalid (e.g. - mService == null || mClientIf == 0)
- Associated - BluetoothDeviceis unavailable
- Device is busy (i.e. a previous request is still in-progress) 
- An Android internal failure occurred (i.e. an underlying - android.os.RemoteExceptionwas thrown)