public void confirmMessage() {
			if(pendingMessage == null) {
				throw new IllegalStateException("Message was confirmed although messageBuffer was not waiting for a confirmation.");
			} else {
				pendingMessage = null;
				deliveredPackages++;
				if(messageBuffer.isEmpty()) {
					long interval = System.currentTimeMillis() - startTime;
					Debugger.println("throughput", "Delivered " + deliveredPackages +" packages in " + interval/1000 + "."+ interval%1000 +" seconds.");
					deliveredPackages = 0;
				}
			}
		}