=doc #3647 Clarify that existing FSM timer is canceled by setTimer

akka-actor/src/main/scala/akka/actor/FSM.scala

@@ -356,6 +356,8 @@ trait FSM[S, D] extends Actor with Listeners with ActorLogging {
 
   /**
    * Schedule named timer to deliver message after given delay, possibly repeating.
+   * Any existing timer with the same name will automatically be canceled before
+   * adding the new timer.
    * @param name identifier to be used with cancelTimer()
    * @param msg message to be delivered
    * @param timeout delay of first message delivery and between subsequent messages

akka-docs/rst/java/lambda-fsm.rst

@@ -332,8 +332,11 @@ You may set a timer using
 
 where :obj:`msg` is the message object which will be sent after the duration
 :obj:`interval` has elapsed. If :obj:`repeat` is :obj:`true`, then the timer is
-scheduled at fixed rate given by the :obj:`interval` parameter. Timers may be
+scheduled at fixed rate given by the :obj:`interval` parameter.
-canceled using
+Any existing timer with the same name will automatically be canceled before
+adding the new timer.
+
+Timers may be canceled using
 
   :func:`cancelTimer(name)`
 

akka-docs/rst/scala/fsm.rst

@@ -362,8 +362,11 @@ You may set a timer using
 
 where :obj:`msg` is the message object which will be sent after the duration
 :obj:`interval` has elapsed. If :obj:`repeat` is :obj:`true`, then the timer is
-scheduled at fixed rate given by the :obj:`interval` parameter. Timers may be
+scheduled at fixed rate given by the :obj:`interval` parameter.
-canceled using
+Any existing timer with the same name will automatically be canceled before
+adding the new timer.
+
+Timers may be canceled using
 
   :func:`cancelTimer(name)`