@JsonProperty("runtime")
	public String getRuntimeStr() {
		long runtimeSecond = (this.finishTime == null || this.startTime == null) ? 0 : this.finishTime.getEpochSecond() - this.startTime.getEpochSecond();
		return ms2Time(runtimeSecond * 1000);
	}
Get Running time in HH:MM:SS style.

@return formatted runtime string
ngrinder-core/src/main/java/org/ngrinder/model/PerfTest.java