r.mu.Lock()
	defer r.mu.Unlock()
	getDst := func(n int) []byte {
		if cap(dst) < n {
			return make([]byte, n)
		}
		return dst[:n]
	}

	if r.w == r.r {
		if r.isFull {
			buf := getDst(r.size)
			copy(buf, r.buf[r.r:])
			copy(buf[r.size-r.r:], r.buf[:r.w])
			return buf
		}
		return nil
	}

	if r.w > r.r {
		buf := getDst(r.w - r.r)
		copy(buf, r.buf[r.r:r.w])

    int index = aValidIndex();
    E initialValue = getList().get(index);
    assertEquals(
        "set(i, x) should return the old element at position i.",
        initialValue,
        getList().set(index, newValue));
    assertEquals("After set(i, x), get(i) should return x", newValue, getList().get(index));
    assertEquals("set() should not change the size of a list.", getNumElements(), getList().size());
  }

  public void testSubList_startNegative() {
    assertThrows(IndexOutOfBoundsException.class, () -> getList().subList(-1, 0));
  }

  public void testSubList_endTooLarge() {
    assertThrows(IndexOutOfBoundsException.class, () -> getList().subList(0, getNumElements() + 1));
  }

  public void testSubList_startGreaterThanEnd() {
    try {
      getList().subList(1, 0);
      fail("subList(1, 0) should throw");

  public void testSubList_startNegative() {
    assertThrows(IndexOutOfBoundsException.class, () -> getList().subList(-1, 0));
  }

  public void testSubList_endTooLarge() {
    assertThrows(IndexOutOfBoundsException.class, () -> getList().subList(0, getNumElements() + 1));
  }

  public void testSubList_startGreaterThanEnd() {
    try {
      getList().subList(1, 0);
      fail("subList(1, 0) should throw");

   */
  public void testAddAtIndex_unsupportedPresent() {
    assertThrows(UnsupportedOperationException.class, () -> getList().add(0, e0()));
    expectUnchanged();
  }

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)
  public void testAddAtIndex_supportedNotPresent() {
    getList().add(0, e3());
    expectAdded(0, e3());
  }

  @CollectionFeature.Require(FAILS_FAST_ON_CONCURRENT_MODIFICATION)

    int index = aValidIndex();
    E initialValue = getList().get(index);
    assertEquals(
        "set(i, x) should return the old element at position i.",
        initialValue,
        getList().set(index, newValue));
    assertEquals("After set(i, x), get(i) should return x", newValue, getList().get(index));
    assertEquals("set() should not change the size of a list.", getNumElements(), getList().size());
  }

     * @return the field value
     * @throws IllegalAccessRuntimeException {@link IllegalAccessException} if an error occurs
     * @see #getInt(Field, Object)
     */
    public static int getInt(final Field field) throws IllegalAccessRuntimeException {
        assertArgumentNotNull("field", field);

        return getInt(field, null);
    }

    /**
     * Returns the value of a {@link Field} as an int.
     *

        ftpInfo = new FtpClient.FtpInfo(value, Constants.UTF_8);
        assertEquals(value, ftpInfo.toUrl());
        assertEquals("123.123.123.123:9999", ftpInfo.getCacheKey());
        assertEquals("123.123.123.123", ftpInfo.getHost());
        assertEquals(9999, ftpInfo.getPort());
        assertEquals("/", ftpInfo.getParent());
        assertNull(ftpInfo.getName());

        value = "ftp://123.123.123.123/test.txt";

        // Next field (4 bytes) - offset to next entry
        int next = bb.getInt();

        // InterfaceIndex (4 bytes)
        int ifIndex = bb.getInt();

        // Capability (4 bytes)
        int capability = bb.getInt();

        // Reserved (4 bytes) - skip
        bb.getInt();

        // LinkSpeed (8 bytes) - in bits per second
        long linkSpeedBps = bb.getLong();

    assertEquals("c", Iterables.getLast(list));
  }

  public void testGetLast_emptyList() {
    List<String> list = emptyList();
    assertThrows(NoSuchElementException.class, () -> Iterables.getLast(list));
  }

  public void testGetLast_sortedSet() {
    SortedSet<String> sortedSet = ImmutableSortedSet.of("b", "c", "a");
    assertEquals("c", Iterables.getLast(sortedSet));
  }