updation of timer doc

ignite/handlers/timing.py

@@ -22,7 +22,8 @@ class Timer:
     Note:
         When using ``Timer(average=True)`` do not forget to call ``timer.step()`` every time an event occurs. See
         the examples below.
-
+    Note:
+        If "Timer" is attached to measure single epoch time, it can also record the time of all handlers attached prior to it. To obtain the actual time taken for the epoch completion, handlers have to be rearranged.
     Examples:
         Measuring total time of the epoch: