anchor.diff:  %% the mechanism is very simple; when there are more than OPS_THRESHOLD
   %% operations for a given key, just perform a read, that will trigger
   %% the GC mechanism.
  --spec op_insert_gc(key(), clocksi_payload(), ets:tid(), ets:tid()) -> true.
  +-spec op_insert_gc(key(), clocksi_payload(), cache_id(), cache_id()) -> true.
   op_insert_gc(Key, DownstreamOp, OpsCache, SnapshotCache)->
       OpsDict = case ets:lookup(OpsCache, Key) of
                     []->
  
positive.code:     end.
  
  %% @doc Get a list of operations from an orddict of operations
  -spec filter_ops(orddict:orddict()) -> {ok, list()}.
  filter_ops(Ops) ->
      MapFun = fun(X) ->
              case X of
  
negative.code: 
  %% @doc Operation to insert a snapshot in the cache and start
  %%      garbage collection triggered by reads.
  -spec snapshot_insert_gc(key(), orddict:orddict(), orddict:orddict(), cache_id(), cache_id()) -> true.
  snapshot_insert_gc(Key, SnapshotDict, OpsDict, SnapshotCache, OpsCache)->
      case (orddict:size(SnapshotDict))==?SNAPSHOT_THRESHOLD of
          true ->
  