code: function(string, t0)
  	{
  		if (mxLog.TRACE)
  		{
  			var dt = (t0 != 0) ? ' ('+(new Date().getTime() - t0)+' ms)' : '';
  			mxLog.writeln('Leaving '+string+dt);
  		}
  	}
docs: Function: leave
  
  Writes the specified string to the console
  if <TRACE> is true and computes the difference
  between the current time and t0 in milliseconds.
  See <enter> for an example.