code: @SuppressWarnings("PMD.LinguisticNaming")
    boolean setAt(int item, int seedIndex) {
      int hash = seeded(item, seedIndex);
      int index = hash >>> tableShift;
      long previous = table[index];
      table[index] |= bitmask(hash);
      return (table[index] != previous);
    }
docs: Sets the membership flag for the computed bit location.
  
  @param item the element's hash
  @param seedIndex the hash seed index
  @return if the membership changed as a result of this operation