anchor.diff:  
       _Config.
   
  +init_per_group(with_binary_padding, Config) ->
  +    [{binary_padding, true}] ++ Config;
   init_per_group(with_sync_join, Config) ->
       [{parallelism, 1}, {sync_join, true}] ++ Config;
   init_per_group(with_monotonic_channels, Config) ->
  
positive.code:       [default_manager_test]},
  
       {with_sync_join, [],
        [default_manager_test]}
      ].
  
  
negative.code:      
       {group, with_monotonic_channels, [parallel]},
  
       {group, with_sync_join, [parallel]},
  
       {group, with_binary_padding, [parallel]}
      ].
  
  groups() ->
  