anchor.diff:  -define(DEFAULT_GC_INTERVAL, 900). %% 15 minutes
   -define(DEFAULT_GC_RETRY_INTERVAL, 21600). %% 6 hours
   -define(DEFAULT_GC_KEY_SUFFIX_MAX, 256).
  --define(DEFAULT_GC_BATCH_SIZE, 1000).
  --define(DEFAULT_GC_WORKERS, 2).
   -define(EPOCH_START, <<"0">>).
   -define(DEFAULT_MAX_SCHEDULED_DELETE_MANIFESTS, 50).
   
  
positive.code:           %% start of the current gc interval
            start_key :: binary(),
            end_key :: binary(),
            batch_size=1 :: pos_integer(),
            %% Used for paginated 2I querying of GC bucket
            continuation :: continuation()
           }).
  
negative.code: %% The name is general so declare local type for readability.
  -type index_result_keys() :: keys().
  
  -define(DEFAULT_GC_BATCH_SIZE, 1000).
  -define(DEFAULT_GC_WORKERS, 2).
  
  -record(gc_batch_state, {
            %% start of the current gc batch
            batch_start :: undefined | non_neg_integer(),
  