docs: public static boolean isInitialAckDRId(long drId) {
          if (drId == -1) return true;
          int clusterId = getClusterIdFromDRId(drId);
          if (clusterId >= 0 && clusterId <= MAX_CLUSTER_ID) {
              return ((drId >>> 63) != 1L) && (getSequenceNumberFromDRId(drId) == MAX_SEQUENCE_NUMBER);
          }
          return false;
      }