anchor.diff:            block_count=0 :: non_neg_integer(),
             leeway :: non_neg_integer(),
             worker_pids=[] :: [pid()],
  -          max_workers=1 :: pos_integer(),
  -          batch_size=1 :: pos_integer(),
  +          max_workers=?DEFAULT_GC_WORKERS :: pos_integer(),
  +          batch_size=?DEFAULT_GC_BATCH_SIZE :: pos_integer(),
             %% Used for paginated 2I querying of GC bucket
             key_list_state :: undefined | gc_key_list_state(),
             %% Options to use when start workers
  
positive.code: %% The name is general so declare local type for readability.
  -type index_result_keys() :: keys().
  
  -record(gc_batch_state, {
            %% start of the current gc batch
            batch_start :: undefined | non_neg_integer(),
  
negative.code: -define(DEFAULT_GC_INTERVAL, 900). %% 15 minutes
  -define(DEFAULT_GC_RETRY_INTERVAL, 21600). %% 6 hours
  -define(DEFAULT_GC_KEY_SUFFIX_MAX, 256).
  -define(EPOCH_START, <<"0">>).
  -define(DEFAULT_MAX_SCHEDULED_DELETE_MANIFESTS, 50).
  
  