anchor.diff:           drop/1,
            is_empty/1,
            callback/3]).
  +
  +%% Helper API
  +-export([key_counts/0]).
   
   -ifdef(TEST).
   -include_lib("eunit/include/eunit.hrl").
  
positive.code: callback(_State, _Ref, _Msg) ->
      ok.
  
  %% ===================================================================
  %% Internal functions
  %% ===================================================================
  
  %% @private
  %% Schedule sync (if necessary)
  
negative.code: -author('Andy Gross <andy@basho.com>').
  -author('Dave Smith <dizzyd@basho.com>').
  
  %% KV Backend API
  -export([start/2,
           stop/1,
           get/2,
  