anchor.diff:  my_split_binary(X, Pos) when byte_size(X) >= Pos ->
       split_binary(X, Pos);
   my_split_binary(_X, _Pos) ->
  -    error('not_enough_data').
  +    throw_error('not_enough_data').
   
   
   -spec parse_field_part/1 :: (
  
positive.code: 
  parse_req_field(Code, ParseValue, L) ->
      case parse_opt_field(Code, ParseValue, L) of
          {'undefined', _Rest} -> error({'missing_field', Code});
          X -> X
      end.
  
  
negative.code:     {{FieldCode, FieldValue}, _Rest} = parse_field(Bytes),
      case FieldCode of
          1 -> FieldValue;
          _ -> throw_error('invalid_toplevel_header')
      end.
  
  
  