+Return the last,first value including its time. The time for
+FIRST is actually the start of the corresponding interval, where
+LASTs time component returns the end of the corresponding interval.
+
+Example: C<VDEF:first=mydata,FIRST>
+
+Z<>
+
+=item TOTAL
+
+Returns the rate from each defined timeslot multiplied with the
+step size. This can for instance return total bytes transfered
+when you have logged bytes per second. The time component returns
+the amount of seconds
+
+Example: C<VDEF:total=mydata,TOTAL>