anchor.diff:  -include_lib("caterpillar_builder_internal.hrl").
   -behaviour(gen_server).
   
  --export([start_link/1]).
  +-export([start_link/1, state/0]).
   -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
            terminate/2, code_change/3, prepare/3]).
   
  
positive.code:             case ets:lookup(State#state.unpack_state, Reference) of
                  [{Reference, Version}|_] ->
                  error_logger:error_msg("preprocess on ~p failed: ~p~n", [Version, Reason]),
                  Subj = io_lib:format("#Unpack error: ~p", [Version]),
                  Body = io_lib:format("Failed to unpack archive ~p: ~p~n", [Version, Reason]),
                  notify(Subj, Body),
                  lists:delete(Version, State#state.queued);
              _Other ->
                  State#state.queued
  
negative.code:         buckets,
          main_queue,
          wait_queue,
          queue_switch=true,
          next_to_build,
          workers=[],
          unpack_state,
  