Timer task is disposed due to `restartTimerOnMaxSize` leading to data loss

[OrezzerO]

Steps to reproduce:

1. Submit data fast enough,
2. If timer is running while buffer is full ,timer task will be disposed.

We can see it in :

influxdb-client-java/client/src/main/java/com/influxdb/client/internal/flowable/FlowableBufferTimedFlushable.java

Lines 156 to 196 in d641b11

	public void onNext(T t) {
	U b;
	synchronized (this) {
	b = buffer;
	if (b == null) {
	return;
	}
	b.add(t);
	if (b.size() < maxSize) {
	return;
	}
	buffer = null;
	producerIndex++;
	}
	if (restartTimerOnMaxSize) {
	timer.dispose();
	}
	fastPathOrderedEmitMax(b, false, this);
	try {
	b = Objects.requireNonNull(bufferSupplier.get(), "The supplied buffer is null");
	} catch (Throwable e) {
	Exceptions.throwIfFatal(e);
	cancel();
	downstream.onError(e);
	return;
	}
	synchronized (this) {
	buffer = b;
	consumerIndex++;
	}
	if (restartTimerOnMaxSize) {
	timer = w.schedulePeriodically(this, timespan, timespan, unit);
	}
	}

This bug will lead to #793. I think setting restartTimerOnMaxSize to false will be a good choice. Or we can add a flag when task is running and do not dispose the timer task.

Specifications:

• Client Version: 6.7.0
• InfluxDB Version: 2.6.1
• JDK Version: 11
• Platform: linux