public void setExecutionStartTime() {
			m_executionStartTime = m_timeAuthority.getTimeInMilliseconds();
		}
{@link net.grinder.engine.process.GrinderProcess} calls {@link #setExecutionStartTime} just before launching
threads, after which it is never called again.
ngrinder-runtime/src/main/java/net/grinder/engine/process/GrinderProcess.java