anchor.diff:  
                       %% Fire post-interposition functions -- trace after wrapping!
                       PostFoldFun = fun(_Name, PostInterpositionFun, ok) ->
  -                        PostInterpositionFun({forward_message, Name, WrappedOriginalMessage}, {forward_message, Name, WrappedMessage}),
  +                        PostInterpositionFun(
  +                            {forward_message, Name, WrappedOriginalMessage},
  +                            {forward_message, Name, WrappedMessage}
  +                        ),
                           ok
                       end,
                       maps:fold(PostFoldFun, ok, PostInterpositionFuns),
  
positive.code:                     %% Acknowledgements.
                      case maps:get(retransmission, Options, false) of
                          false ->
                              RescheduleableMessage = {forward_message, From, Name, Channel, MessageClock, PartitionKey, ServerRef, OriginalMessage, Options},
                              partisan_acknowledgement_backend:store(MessageClock, RescheduleableMessage);
                          true ->
                              ok
                      end,
  
                      %% Send message along.
                      do_send_message(Name,
                                      Channel,
                                      PartitionKey,
                                      WrappedMessage,
                                      Options,
                                      PreInterpositionFuns)
              end,
  
              case From of
  
negative.code: 
                      %% Return clock and wrapped message.
                      {LocalClock, CausalMessage};
  
                  _ ->
                      %% Retransmission.
                      %% Get the clock and message we used last time.
                      {ok, LocalClock, CausalMessage} =
                          partisan_causality_backend:reemit(CausalLabel, Clock),
  
                      %% Return clock and wrapped message.
                      {LocalClock, CausalMessage}
  