public void stop() {
        if (finalized) throw new IllegalStateException("Metrics have been finalized and cannot be modified");
        if (-1 == this.tempTime) throw new IllegalStateException("Internal Error: Metrics has not been started. Start timer before stopping timer");
        this.durationNs = this.durationNs + (System.nanoTime() - this.tempTime);
        this.tempTime = -1;
    }
Stops the timer for this metric and increments the overall duration. Should not be called without first calling
{@link #start()}.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/util/MutableMetrics.java