anchor.diff:  
   %% @doc When a node is connected, return the state, membership and outgoing message queue to be transmitted.
   join(#full_v1{membership=Membership0} = State0, _Node, #full_v1{membership=NodeMembership}) ->
  -    Membership = ?SET:merge(Membership0, NodeMembership),
  +    Membership = partisan_membership_set:merge(Membership0, NodeMembership),
       State = State0#full_v1{membership=Membership},
       MembershipList = membership_list(State),
       OutgoingMessages = gossip_messages(State),
  
positive.code:          periodic/1,
           handle_message/2]).
  
  -define(SET, partisan_membership_set).
  
  -record(full_v1, {
      actor           ::  actor(),
      membership      ::  partisan_membership_set:t()
  
negative.code: 
  %% @private
  new_state(Actor) ->
      {ok, Membership} = partisan_membership_set:add(myself(), Actor, partisan_membership_set:new()),
      LocalState = #full_v1{membership=Membership, actor=Actor},
      persist_state(LocalState),
      LocalState.
  