anchor.diff:        [causal_test]},
   
        {with_causal_send, [],
  +      [default_manager_test]},
  +     
  +     {with_causal_send_and_ack, [],
         [default_manager_test]},
   
        {with_forward_interposition, [],
  
positive.code:      {group, with_causal_labels, []},
  
       {group, with_causal_send, []},
  
       {group, with_forward_interposition, []},
  
  
negative.code:     [{causal_labels, [default]}] ++ Config;
  init_per_group(with_causal_send, Config) ->
      [{causal_labels, [default]}, {forward_options, [{causal_label, default}]}] ++ Config;
  init_per_group(with_causal_send_and_ack, Config) ->
      [{causal_labels, [default]}, {forward_options, [{causal_label, default}, {ack, true}]}] ++ Config;
  init_per_group(with_forward_interposition, Config) ->
      [{disable_fast_forward, true}] ++ Config;
  init_per_group(with_receive_interposition, Config) ->
  