docs: public void handleMergeRequest(Address sender, MergeId merge_id, Collection<? extends Address> mbrs) {
          try {
              _handleMergeRequest(sender, merge_id, mbrs);
          }
          catch(Throwable t) {
              log.error("%s: failure handling the merge request: %s", gms.local_addr, t.getMessage());
              cancelMerge(merge_id);
              sendMergeRejectedResponse(sender, merge_id);
          }
      }