code: function(t_now, data) {
  		var t_done = t_now;
  
  		// xhr beacon with detailed timing information
  		if (data && data.timing && data.timing.loadEventEnd) {
  			t_done = data.timing.loadEventEnd;
  		}
  		// Boomerang loaded late and...
  		else if (BOOMR.loadedLate) {
  			// We have navigation timing,
  			if(w.performance && w.performance.timing) {
  				// and boomerang loaded after onload fired
  				if(w.performance.timing.loadEventStart && w.performance.timing.loadEventStart < BOOMR.t_end) {
  					t_done = w.performance.timing.loadEventStart;
  				}
  			}
  			// We don't have navigation timing,
  			else {
  				// So we'll just use the time when boomerang was added to the page
  				// Assuming that this means boomerang was added in onload
  				t_done = BOOMR.t_lstart || BOOMR.t_start || t_now;
  			}
  		}
  
  		return t_done;
  	}
docs: Validate that the time we think is the load time is correct.  This can be wrong if boomerang was loaded
  after onload, so in that case, if navigation timing is available, we use that instead.