* The race can happen if the MemberRemoved event is received followed by a Delta update from
a node that has not yet got the MemberRemoved. That will make the bucket for the removed
node to be added back in the registry.
* because it is not referentially transparent; normally we reserved parens for
side-effecting code but given how people thoughtlessly close over it we revised
that that decision for sender
* caller can still omit parens
* Replace (deprecate) akka.cluster.auto-down config setting with
akka.cluster.auto-down-unreachable-after
* AutoDown actor that keeps track of unreachable members
and performs down from the leader node when they have been
unreachable for the specified duration
* Migration guide
if the message should be sent to a matching path on the sender node or not.
Added optional property (skipSenderNode) to PubSub.SendToAll.
Deciding if the SendToAll message should be sent to a matching path on the sender cluster node or not. + Test and Docs.
