code: private static QueryCacheEventData createEndOfSequenceEvent(int partitionId) {
          return QueryCacheEventDataBuilder.newQueryCacheEventDataBuilder(false)
                  .withSequence(END_SEQUENCE).withPartitionId(partitionId).build();
      }
docs: In graceful shutdown, we are flushing all unsent events in an {@code Accumulator}. This event
  will be the last event of an {@code Accumulator} upon flush and it is used to inform subscriber-side
  to state that we reached the end of event sequence for the relevant partition.
  <p/>
  After this event received by subscriber-side, subscriber resets its next-expected-sequence counter to zero for the
  corresponding partition.