anchor.diff:           my_range       = undefined                               :: undefined | intervals:interval(),
            fb_dest_pid    = undefined                               :: undefined | comm:mypid(),
            fb_send_kvv    = []                                      :: OutdatedOnOther::kvv_list(),
  +         fb_had_kvv_req = false                                   :: NonEmptyReqList::boolean(),
            fb_send_kvv_req= []                                      :: RequestedByOther::kvv_list(),
            other_kv_tree  = gb_trees:empty()                        :: MyIOtherKvTree::gb_tree(),
            send_stats     = undefined                               :: undefined | comm:mypid(),
  
positive.code:         case FBDest of
              undefined ->
                  0;
              _ when FbReqKVV =:= [] ->
                  send_request_resolve(FBDest, {?key_upd, FbKVV, []},
                                       Stats#resolve_stats.session_id,
                                       FromMyNode, undefined, [], true);
  
negative.code:     % allow the garbage collection to clean up the ReqKeys here:
      % also update the KvvList
      State#rr_resolve_state{operation = {?key_upd, MyIOtherKvvList, []},
                             other_kv_tree = MyIOtherKvTree,
                             fb_had_kvv_req = ReqKeys =/= []};
  
  on({get_entries_response, EntryList}, State =
         #rr_resolve_state{ operation = {?key_upd, MyIOtherKvvList, []},
  