@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)

   *   <li>clearing weak references to unreachable referents
   *   <li>enqueuing weak references to unreachable referents in their reference queue
   * </ul>
   */
  @DoNotMock("Implement with a lambda")
  public interface FinalizationPredicate {
    boolean isDone();
  }

  /**
   * Waits until the given weak reference is cleared, invoking the garbage collector as necessary to

@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.

  @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)

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

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

   *
   * <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}
   *

      this.strong = true;
      return this;
    }

    /**
     * Instructs the {@link InternerBuilder} to build a weak interner.
     *
     * @see Interners#newWeakInterner()
     */
    @CanIgnoreReturnValue
    @GwtIncompatible // java.lang.ref.WeakReference
    public InternerBuilder weak() {
      this.strong = false;
      return this;
    }

    /**

    return delegate().poll();
  }

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

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

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

  /**

    // other threads waiting on take() will also return.
    if (result == DEAD_LETTER) responseQueue.add(DEAD_LETTER)

    return result
  }

  public override fun peek(): MockResponse = responseQueue.peek() ?: failFastResponse ?: super.peek()

  public open fun enqueue(response: MockResponse) {
    responseQueue.add(response)
  }

  public open fun clear() {
    responseQueue.clear()
  }

        && builder.getValueStrength() == Strength.WEAK) {
      return new MapMakerInternalMap<>(builder, StrongKeyWeakValueEntry.Helper.instance());
    }
    if (builder.getKeyStrength() == Strength.WEAK
        && builder.getValueStrength() == Strength.STRONG) {
      return new MapMakerInternalMap<>(builder, WeakKeyStrongValueEntry.Helper.instance());
    }
    if (builder.getKeyStrength() == Strength.WEAK && builder.getValueStrength() == Strength.WEAK) {