Fix IActorRef leaks in AddressTerminatedTopic when entity terminates …

…immediately after unwatching a remote actor. (#4305) (#4308)

Co-authored-by: Petri Kero <[email protected]>

src/core/Akka/Actor/ActorCell.DeathWatch.cs

@@ -176,7 +176,10 @@ protected void TellWatchersWeDied()
             }
             finally
             {
-                _state = _state.ClearWatching();
+                MaintainAddressTerminatedSubscription(() =>
+                {
+                    _state = _state.ClearWatchedBy();
+                });
             }
         }
 

src/core/Akka/ActorState.cs

@@ -60,6 +60,11 @@ internal interface IActorState
         /// <returns>TBD</returns>
         IActorState ClearWatching();
         /// <summary>
+        /// Clears the `WatchedBy` set
+        /// </summary>
+        /// <returns>TBD</returns>
+        IActorState ClearWatchedBy();
+        /// <summary>
         /// Clears the `Termination queue` set
         /// </summary>
         /// <returns>TBD</returns>
@@ -312,6 +317,16 @@ public IActorState ClearWatching()
             return this;
         }
 
+        /// <summary>
+        /// TBD
+        /// </summary>
+        /// <returns>TBD</returns>
+        public IActorState ClearWatchedBy()
+        {
+            _watchedBy = null;
+            return this;
+        }
+
         /// <summary>
         /// TBD
         /// </summary>
@@ -547,6 +562,17 @@ public IActorState ClearWatching()
         }
 
 
+        /// <summary>
+        /// TBD
+        /// </summary>
+        /// <returns>TBD</returns>
+        public IActorState ClearWatchedBy()
+        {
+            _watchedBy.Clear();
+            return this;
+        }
+
+
         /// <summary>
         /// TBD
         /// </summary>