anchor.diff:  unpack(Maybe_Options) ->
       [Options, Maybe_Messages] = unpack(Maybe_Options, orddict:new()),
       Dict_Options = orddict:store(options, Options, orddict:new()),
  -    {ok, Dict_Options, Maybe_Messages}.
  +    {ok, {ppspp_options, Dict_Options}, Maybe_Messages}.
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   unpack( <<?PPSPP_SUPPORTED_VERSION,
             Version:?BYTE,
  
positive.code:               ppspp_option/0]).
  
  -opaque root_hash() :: binary().
  -opaque ppspp_options() :: list({ ppspp_option(), any()}).
  -type ppspp_option() :: supported_version
  | minimum_version
  | swarm_id
  
negative.code: -spec use_default_options(root_hash()) -> ppspp_options().
  
  use_default_options(Root_Hash) when is_binary(Root_Hash) ->
      {ppspp_options, orddict:from_list( [{swarm_id, Root_Hash},
                          {chunk_addressing_method, chunking_32bit_chunks},
                          {chunk_size, ?PPSPP_DEFAULT_CHUNK_SIZE},
                          {content_integrity_check_method, merkle_hash_tree},
                          {merkle_hash_tree_function, sha},
                          {minimum_version, ?PPSPP_RFC_VERSION},
                          {version, ?PPSPP_RFC_VERSION}])}.
  
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  %% @doc pack an orddict of ppspp erlang terms into a binary PPSPP message segment
  