*
   * @since 10.0
   */
  @DoNotMock
  public abstract static class Builder<E> {
    static final int DEFAULT_INITIAL_CAPACITY = 4;

    static int expandedCapacity(int oldCapacity, int minCapacity) {
      if (minCapacity < 0) {
        throw new AssertionError("cannot store more than MAX_VALUE elements");
      }
      // careful of overflow!

   *
   * @since 10.0
   */
  @DoNotMock
  public abstract static class Builder<E> {
    static final int DEFAULT_INITIAL_CAPACITY = 4;

    static int expandedCapacity(int oldCapacity, int minCapacity) {
      if (minCapacity < 0) {
        throw new AssertionError("cannot store more than MAX_VALUE elements");
      }
      // careful of overflow!

         * amortized O(n log n) performance.  Therefore, ensure there are at least O(n) *unused*
         * spaces in the builder array.
         */
        int newLength = ImmutableCollection.Builder.expandedCapacity(n, n + 1);
        if (newLength > elements.length) {
          elements = Arrays.copyOf(elements, newLength);
        }
      }
      elements[n++] = element;
      return this;
    }

    /**

     * elements.
     */
    private void ensureCapacity(int minCapacity) {
      if (minCapacity > dedupedElements.length) {
        int newCapacity =
            ImmutableCollection.Builder.expandedCapacity(dedupedElements.length, minCapacity);
        dedupedElements = Arrays.copyOf(dedupedElements, newCapacity);
      }
    }

      this.size = 0;
    }

    private void getReadyToExpandTo(int minCapacity) {
      if (contents.length < minCapacity) {
        this.contents = Arrays.copyOf(contents, expandedCapacity(contents.length, minCapacity));
        forceCopy = false;
      } else if (forceCopy) {
        contents = Arrays.copyOf(contents, contents.length);
        forceCopy = false;
      }
    }

    /**

      if (minCapacity * 2 > alternatingKeysAndValues.length) {
        alternatingKeysAndValues =
            Arrays.copyOf(
                alternatingKeysAndValues,
                ImmutableCollection.Builder.expandedCapacity(
                    alternatingKeysAndValues.length, minCapacity * 2));
        entriesUsed = false;
      }
    }

    /**

    }

    private void ensureCapacity(int minCapacity) {
      if (minCapacity > entries.length) {
        entries =
            Arrays.copyOf(
                entries, ImmutableCollection.Builder.expandedCapacity(entries.length, minCapacity));
        entriesUsed = false;
      }
    }

    /**
     * Associates {@code key} with {@code value} in the built map. If the same key is put more than

      this.values = new @Nullable Object[initialCapacity];
    }

    private void ensureCapacity(int minCapacity) {
      if (minCapacity > keys.length) {
        int newCapacity = ImmutableCollection.Builder.expandedCapacity(keys.length, minCapacity);
        this.keys = Arrays.copyOf(keys, newCapacity);
        this.values = Arrays.copyOf(values, newCapacity);
      }
    }

    /**