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(

    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(

   *
   * <p>Calls to {@code peek()} should not change the state of the iteration, except that it
   * <i>may</i> prevent removal of the most recent element via {@link #remove()}.
   *
   * @throws NoSuchElementException if the iteration has no more elements according to {@link
   *     #hasNext()}
   */
  @ParametricNullness
  E peek();

  /**
   * {@inheritDoc}
   *

  @CollectionSize.Require(ZERO)
  public void testPeek_empty() {
    assertNull("emptyQueue.peek() should return null", getQueue().peek());
    expectUnchanged();
  }

  @CollectionSize.Require(ONE)
  public void testPeek_size1() {
    assertEquals("size1Queue.peek() should return first element", e0(), getQueue().peek());
    expectUnchanged();
  }

  @CollectionFeature.Require(KNOWN_ORDER)

   *
   * <p>Calls to {@code peek()} should not change the state of the iteration, except that it
   * <i>may</i> prevent removal of the most recent element via {@link #remove()}.
   *
   * @throws NoSuchElementException if the iteration has no more elements according to {@link
   *     #hasNext()}
   */
  @ParametricNullness
  E peek();

  /**
   * {@inheritDoc}
   *

  }

  @CanIgnoreReturnValue
  @Override
  @ParametricNullness
  public E remove() {
    return delegate().remove();
  }

  @Override
  @CheckForNull
  public E peek() {
    return delegate().peek();
  }

  @Override
  @ParametricNullness
  public E element() {
    return delegate().element();
  }

  /**

@Throws(EOFException::class)
private fun Buffer.readChallengeHeader(result: MutableList<Challenge>) {
  var peek: String? = null

  while (true) {
    // Read a scheme name for this challenge if we don't have one already.
    if (peek == null) {
      skipCommasAndWhitespace()
      peek = readToken()
      if (peek == null) return
    }

    val schemeName = peek

    // Read a token68, a sequence of parameters, or nothing.

            }
          }
        };

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

    assertEquals(1, (int) iter.peek());
    assertEquals(1, (int) iter.next());

    /*
     * We test peek() after various calls to make sure that one bad call doesn't interfere with its

            }
          }
        };

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

    assertEquals(1, (int) iter.peek());
    assertEquals(1, (int) iter.next());

    /*
     * We test peek() after various calls to make sure that one bad call doesn't interfere with its

    assertTrue(queue.add("hi"));
    assertEquals("hi", queue.element());
    assertEquals("hi", queue.peek());
    assertEquals(1, queue.size());
    assertEquals(0, queue.remainingCapacity());

    assertTrue(queue.add("there"));
    assertEquals("there", queue.element());
    assertEquals("there", queue.peek());
    assertEquals(1, queue.size());
    assertEquals(0, queue.remainingCapacity());