public boolean addDescriptor(BluetoothGattDescriptor descriptor) {
        mDescriptors.add(descriptor);
        descriptor.setCharacteristic(this);
        return true;
    }
Used for mocks and constants in rxandroidble, but instances created in mockrxandroidble, so the methods must be implemented
rxandroidble/src/test/java/android/bluetooth/BluetoothGattCharacteristic.java