add(e);
        }
      } else {
        super.add(elements);
      }
      return this;
    }

    private void addDeduping(E element) {
      requireNonNull(hashTable); // safe because we check for null before calling this method
      int mask = hashTable.length - 1;
      int hash = element.hashCode();
      for (int i = Hashing.smear(hash); ; i++) {
        i &= mask;
        Object previous = hashTable[i];

     * affect this SetBuilderImpl or sets constructed from this SetBuilderImpl via build().
     */
    abstract SetBuilderImpl<E> copy();

    /**
     * Call this before build(). Does a final check on the internal data structures, e.g. shrinking
     * unnecessarily large structures or detecting previously unnoticed hash flooding.
     */
    SetBuilderImpl<E> review() {
      return this;
    }