@NonNull
	protected WaitForValueChangedRequest waitForIndication(@Nullable final BluetoothGattCharacteristic characteristic) {
		return Request.newWaitForIndicationRequest(characteristic)
				.setRequestHandler(requestHandler);
	}
Sets a one-time callback that will be notified when the value of the given characteristic
changes. This is a blocking request, so the next request will be executed after the
indication was received.
<p>
If {@link WaitForValueChangedRequest#merge(DataMerger)} was used, the whole message will be
completed before the callback is notified.
<p>
The returned request must be either enqueued using {@link Request#enqueue()} for
asynchronous use, or awaited using await() in synchronous execution.

@param characteristic the characteristic that value is expect to change.
@return The request.
ble/src/main/java/no/nordicsemi/android/ble/BleManager.java