anchor.diff:  
       State = #state{buffer = <<>>,
                      buffer_size = 0,
  +                   outstanding_size = 0,
  +                   buffer_overflow = false,
  +                   dropped_messages = 0,
                      batch_size = BatchSize,
                      batch_timeout = BatchTimeout,
  +                   buffer_size_max = BufferSizeMax,
                      worker = Worker},
   
       {ok, State}.
  
positive.code:           file :: file:io_device(),
            file_size :: integer(),
            file_inode :: integer(),
  
            rotation_size :: non_neg_integer(),
            rotation_num_files :: pos_integer(),
  
negative.code: 
      BatchSize = proplists:get_value(batch_size, Opts, 524288),
      BatchTimeout = proplists:get_value(batch_timeout, Opts, 1000),
      BufferSizeMax = proplists:get_value(buffer_size_max, Opts, BatchSize * 10),
  
      RotationConf = proplists:get_value(rotation, Opts, []),
  
  