public void setPossibleDuplicate(boolean possibleDuplicate) {
    setEventFlag(EventFlags.FLAG_POSSIBLE_DUPLICATE, possibleDuplicate);
  }
If the operation encapsulated by this event has already been seen by the region to which it
pertains, this flag should be set to true.

@param possibleDuplicate the possibleDuplicate to set
geode-core/src/main/java/org/apache/geode/internal/cache/EntryEventImpl.java