throw t;
    }
  }

  /** Calls threadFail with message "should throw exception". */
  public void threadShouldThrow() {
    threadFail("should throw exception");
  }

  /** Calls threadFail with message "should throw" + exceptionName. */
  public void threadShouldThrow(String exceptionName) {
    threadFail("should throw " + exceptionName);
  }

  /**

   *
   * @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

   *
   * @throws NoSuchFileException if the file does not exist <i>(optional specific exception)</i>
   * @throws NotDirectoryException if the file could not be opened because it is not a directory
   *     <i>(optional specific exception)</i>
   * @throws IOException if an I/O error occurs
   */
  public static ImmutableList<Path> listFiles(Path dir) throws IOException {

   *
   * @throws NoSuchFileException if the file does not exist <i>(optional specific exception)</i>
   * @throws NotDirectoryException if the file could not be opened because it is not a directory
   *     <i>(optional specific exception)</i>
   * @throws IOException if an I/O error occurs
   */
  public static ImmutableList<Path> listFiles(Path dir) throws IOException {

   * added.
   *
   * @throws NullPointerException if {@code exceptions} is null
   * @throws IllegalArgumentException if {@code exceptions} is empty
   */
  static RuntimeException create(Collection<? extends Throwable> exceptions) {
    if (exceptions.size() == 0) {
      throw new IllegalArgumentException("Can't create an ExceptionCollection with no exceptions");
    }

    protected abstract long makeKey ( Request request ) throws IOException;


    protected abstract Long peekKey () throws IOException;


    protected abstract void doSend ( Request request ) throws IOException;


    protected abstract void doRecv ( Response response ) throws IOException;


    protected abstract void doSkip ( Long key ) throws IOException;


    /**
     * 

   *     an {@code IOException}.
   * @see Closeables#close
   */
  public static void flush(Flushable flushable, boolean swallowIOException) throws IOException {
    try {
      flushable.flush();
    } catch (IOException e) {
      if (swallowIOException) {
        logger.log(Level.WARNING, "IOException thrown while flushing Flushable.", e);
      } else {
        throw e;
      }
    }
  }

  /**

    for (Thread t : threads) {
      t.join();
    }

    if (thrown.get() != null) {
      throw thrown.get();
    }
    assertEquals(1, count.get());
  }

  @J2ktIncompatible
  @GwtIncompatible // Thread
  @SuppressWarnings("ThreadPriorityCheck") // doing our best to test for races
  public void testSynchronizedSupplierThreadSafe() throws InterruptedException {
    final Supplier<Integer> nonThreadSafe =

    for (Thread t : threads) {
      t.join();
    }

    if (thrown.get() != null) {
      throw thrown.get();
    }
    assertEquals(1, count.get());
  }

  @J2ktIncompatible
  @GwtIncompatible // Thread
  @SuppressWarnings("ThreadPriorityCheck") // doing our best to test for races
  public void testSynchronizedSupplierThreadSafe() throws InterruptedException {
    final Supplier<Integer> nonThreadSafe =

    final int throwAfterCount;
    final RuntimeException thrown;
    int count;

    ThrowingRunnable(int throwAfterCount, RuntimeException thrown) {
      this.throwAfterCount = throwAfterCount;
      this.thrown = thrown;
    }

    @Override
    public void run() {
      if (++count >= throwAfterCount) {
        throw thrown;
      }
    }
  }