Google Apps Script Trigger: How to get timer time?

Question

I need to get the timer time of a trigger to show it on a Google Sheet. However, I cannot find the detail.

var triggers = ScriptApp.getProjectTriggers();
for (var i = 0; i < triggers.length; i++) {
     if (triggers[i].getEventType() == ScriptApp.EventType.CLOCK) {
     }
}