@NonNull
	protected final BluetoothGattDescriptor sharedDescriptor(@NonNull final UUID uuid,
															 @DescriptorPermissions final int permissions,
															 @Nullable final Data initialValue) {
		return sharedDescriptor(uuid, permissions, initialValue != null ? initialValue.getValue() : null);
	}
A helper method that creates a descriptor with given UUID and permissions.
Optionally, an initial value may be set.
<p>
The value of the characteristic is shared between clients. A value written by one of the
connected clients will be available for all other clients. To create a sandboxed characteristic,
use {@link #characteristic(UUID, int, int, byte[], BluetoothGattDescriptor...)} instead.

@param uuid The characteristic UUID.
@param permissions The bit mask or characteristic permissions. See {@link BluetoothGattCharacteristic}
                   for details.
@param initialValue The optional initial value of the characteristic.
@return The characteristic.
ble/src/main/java/no/nordicsemi/android/ble/BleServerManager.java