* stack so that it is returned by the next call to {@link Iterator#next()}. If the element is
     * not in {@link #nextElements}, this method throws an {@link UnknownElementException}.
     *
     * <p>This method is used when testing iterators without a known ordering. We poll the target
     * iterator's next element and pass it to the reference iterator through this method so it can

    assertEquals(
        "next() should still return first element after peeking", "A", peekingIterator.next());

    assertEquals("Should be able to peek() at middle element", "B", peekingIterator.peek());
    assertEquals(
        "Should be able to peek() middle element multiple times", "B", peekingIterator.peek());
    assertEquals(

   *
   * If this flag is set, the next four
   * bytes represent the mask key. These bytes appear after any additional bytes specified by [B1_MASK_LENGTH].
   */
  internal const val B1_FLAG_MASK = 128

  /**
   * Byte 1 mask for the payload length.
   *
   * If this value is [PAYLOAD_SHORT], the next two
   * bytes represent the length. If this value is [PAYLOAD_LONG], the next eight bytes
   * represent the length.
   */

    }

    /**
     * Checks if a next page exists after the current page.
     *
     * @return true if a next page exists, false otherwise
     */
    public boolean isExistNextPage() {
        return existNextPage;
    }

    /**
     * Sets whether a next page exists after the current page.
     *
     * @param existNextPage true if a next page exists, false otherwise
     */

    }

    /**
     * Checks if a next page exists.
     *
     * @return true if a next page exists, false otherwise
     */
    public boolean isExistNextPage() {
        return existNextPage;
    }

    /**
     * Sets whether a next page exists.
     *
     * @param existNextPage true if a next page exists, false otherwise
     */

            }
          }
        };

    assertTrue(iter.hasNext());
    assertEquals(0, (int) iter.next());

    // verify idempotence of hasNext()
    assertTrue(iter.hasNext());
    assertTrue(iter.hasNext());
    assertTrue(iter.hasNext());
    assertEquals(1, (int) iter.next());

    assertFalse(iter.hasNext());

    // Make sure computeNext() doesn't get invoked again

    }

    /**
     * Returns true if a next page exists.
     *
     * @return True if a next page exists.
     */
    public boolean isExistNextPage() {
        return existNextPage;
    }

    /**
     * Sets whether a next page exists.
     *
     * @param existNextPage True if a next page exists.
     */
    public void setExistNextPage(final boolean existNextPage) {

            }
          }
        };

    assertTrue(iter.hasNext());
    assertEquals(0, (int) iter.next());

    // verify idempotence of hasNext()
    assertTrue(iter.hasNext());
    assertTrue(iter.hasNext());
    assertTrue(iter.hasNext());
    assertEquals(1, (int) iter.next());

    assertFalse(iter.hasNext());

    // Make sure computeNext() doesn't get invoked again

            }
          }
        };

    assertTrue(iter.hasNext());
    assertEquals(0, (int) iter.next());

    // verify idempotence of hasNext()
    assertTrue(iter.hasNext());
    assertTrue(iter.hasNext());
    assertTrue(iter.hasNext());
    assertEquals(1, (int) iter.next());

    assertFalse(iter.hasNext());

    // Make sure computeNext() doesn't get invoked again

    }

    /**
     * Checks if a next page exists.
     *
     * @return True if a next page exists, false otherwise
     */
    public boolean isExistNextPage() {
        return existNextPage;
    }

    /**
     * Sets whether a next page exists.
     *
     * @param existNextPage True if a next page exists
     */