},
		{
			val:   0.79,
			label: labels[2],
		},
	}
	ticker := time.NewTicker(1 * time.Millisecond)
	defer ticker.Stop()
	for _, obs := range observations {
		// Send observations once every 1ms, to simulate delay between
		// observations. This is to test the channel based
		// synchronization used internally.
		<-ticker.C
		ttfbHist.With(prometheus.Labels{"api": obs.label}).Observe(obs.val)
	}

    }

    public ReservedPortRange reservePortRange() {
        Pair<Integer, Integer> portRange = getNextPortRange(reservations.size());
        ReservedPortRange range = portRangeFactory.getReservedPortRange(portRange.getLeft(), portRange.getRight());
        reservations.add(range);
        return range;
    }