anchor.diff:              {reply, ok, State}
       end;
   
  -handle_call({join, #{name := _Name} = Node},
  +handle_call({join, #{name := Name} = Node},
               _From,
               State0) ->
  -    %% Perform join.
  -    State = internal_join(Node, State0),
  -
  -    %% Return.
  -    {reply, ok, State};
  -
  -handle_call({sync_join, #{name := _Name} = Node},
  +    case node() of
  +        Name ->
  +            %% Ignoring self join.
  +            {reply, ok, State0};
  +        _ ->
  +            %% Perform join.
  +            State = internal_join(Node, State0),
  +
  +            %% Return.
  +            {reply, ok, State}
  +    end;
  +
  +handle_call({sync_join, #{name := Name} = Node},
               From,
               State0) ->
  -    %% Perform join.
  -    State = sync_internal_join(Node, From, State0),
  -
  -    %% Return.
  -    {noreply, State};
  +    lager:info("Starting synchronous join to ~p from ~p", [Node, node()]),
  +
  +    case node() of
  +        Name ->
  +            %% Ignoring self join.
  +            {reply, ok, State0};
  +        _ ->
  +            %% Perform join.
  +            State = sync_internal_join(Node, From, State0),
  +
  +            %% Return.
  +            {reply, ok, State}
  +    end;
   
   handle_call({send_message, Name, Channel, Message}, _From,
               #state{connections=Connections}=State) ->
  
positive.code:                       membership=Membership0,
                        sync_joins=SyncJoins0,
                        connections=Connections}=State) ->
      case lists:member(Node, Pending0) of
          true ->
              %% Move out of pending.
  
negative.code:                 {Node, FromPid} ->
                      case fully_connected(Node, Connections) of
                          true ->
                              lager:info("Node ~p is fully connected.", [Node]),
                              gen_server:reply(FromPid, ok),
                              lists:keydelete(FromPid, 2, SyncJoins0);
                          _ ->
  