Javadoc
This method computes the timeout for sending a batch of events over HTTP, based on how much time it took to
populate that batch. The idea is that if it took X milliseconds to fill the batch, we couldn't wait for more than
X *
HttpEmitterConfig#httpTimeoutAllowanceFactor milliseconds to send that data, because at the same time
the next batch is probably being filled with the same speed, so we have to keep up with the speed.
Ideally it should use something like moving average instead of plain last batch fill time in order to accomodate
for emitting bursts, but it might unnecessary because Druid application might not produce events in bursts.