@Override
  public final void tearDown() {
    try {
      sloppyTearDown();
    } catch (Throwable t) {
      logger.log(Level.INFO, "exception thrown during tearDown: " + t.getMessage(), t);
    }
  }

  public abstract void sloppyTearDown() throws Exception;

    protected abstract void makeKey( Request request ) throws IOException;
    protected abstract Request peekKey() throws IOException;
    protected abstract void doSend( Request request ) throws IOException;
    protected abstract void doRecv( Response response ) throws IOException;
    protected abstract void doSkip() throws IOException;

    public synchronized void sendrecv( Request request,

   *
   * @param timeout the maximum time to wait
   * @throws TimeoutException if the service has not reached the given state within the deadline
   * @throws IllegalStateException if the service {@linkplain State#FAILED fails}.
   * @since 28.0
   */
  default void awaitTerminated(Duration timeout) throws TimeoutException {
    awaitTerminated(toNanosSaturated(timeout), TimeUnit.NANOSECONDS);
  }

  /**

   *
   * @throws X if {@code get} throws any checked exception except for an {@code ExecutionException}
   *     whose cause is not itself a checked exception
   * @throws UncheckedExecutionException if {@code get} throws an {@code ExecutionException} with a
   *     {@code RuntimeException} as its cause
   * @throws ExecutionError if {@code get} throws an {@code ExecutionException} with an {@code

   * ContiguousSet}.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Use {@link #create}.
   */
  @Deprecated
  @DoNotCall("Always throws UnsupportedOperationException")
  public static <E> ImmutableSortedSet.Builder<E> builder() {
    throw new UnsupportedOperationException();
  }

  // redeclare to help optimizers with b/310253115

   * @param unit the time unit of the timeout argument
   * @throws TimeoutException if the service has not reached the given state within the deadline
   * @throws IllegalStateException if the service {@linkplain State#FAILED fails}.
   * @since 15.0
   */
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  void awaitTerminated(long timeout, TimeUnit unit) throws TimeoutException;

  /**

   * sees an Error?
   */
  @AndroidIncompatible
  public void testTaskThrowsError() throws Exception {
    class MyError extends Error {}
    final CyclicBarrier barrier = new CyclicBarrier(2);
    // we need to make sure the error gets thrown on a different thread.
    ExecutorService service = Executors.newSingleThreadExecutor();
    try {

   * null will be returned.
   *
   * @throws ParameterNotInstantiableException if the static methods cannot be invoked because the
   *     default value of a parameter cannot be determined.
   * @throws IllegalAccessException if the class isn't public or is nested inside a non-public
   *     class, preventing its methods from being accessible.
   * @throws InvocationTargetException if a static method threw exception.
   */

   * {@code null}; it may either return a non-null value or throw an exception.
   *
   * <p>No observable state associated with this cache is modified until loading completes.
   *
   * @throws ExecutionException if a checked exception was thrown while loading the value
   * @throws UncheckedExecutionException if an unchecked exception was thrown while loading the
   *     value
   * @throws ExecutionError if an error was thrown while loading the value

   * @param len an int specifying the number of bytes to read.
   * @throws EOFException if this stream reaches the end before reading all the bytes.
   * @throws IOException if an I/O error occurs.
   */
  public static void readFully(InputStream in, byte[] b, int off, int len) throws IOException {
    int read = read(in, b, off, len);
    if (read != len) {
      throw new EOFException(