@CanIgnoreReturnValue
  public final StringBuilder appendTo(StringBuilder builder, Iterator<?> parts) {
    try {
      appendTo((Appendable) builder, parts);
    } catch (IOException impossible) {
      throw new AssertionError(impossible);
    }
    return builder;
  }

  /**
   * Appends the string representation of each of {@code parts}, using the previously configured

   *     failure = t;
   *   }
   * }
   * if (failure != null) {
   *   throwIfInstanceOf(failure, BarException.class);
   *   throwIfUnchecked(failure);
   *   throw new AssertionError(failure);
   * }
   * </pre>
   *
   * @since 20.0
   */
  @GwtIncompatible // Class.cast, Class.isInstance
  public static <X extends Throwable> void throwIfInstanceOf(

  @Test
  fun webSocketAndNetworkInterceptors() {
    client =
      client
        .newBuilder()
        .addNetworkInterceptor(
          Interceptor { chain: Interceptor.Chain? ->
            throw AssertionError() // Network interceptors don't execute.
          },
        ).build()
    webServer.enqueue(
      MockResponse
        .Builder()
        .webSocketUpgrade(serverListener)
        .build(),
    )

  }

  @Override
  Collection<V> createValues() {
    return new FilteredMultimapValues<>(this);
  }

  @Override
  Iterator<Entry<K, V>> entryIterator() {
    throw new AssertionError("should never be called");
  }

  @Override
  Map<K, Collection<V>> createAsMap() {
    return new AsMap();
  }

  @Override
  Set<K> createKeySet() {
    return asMap().keySet();
  }

    try {
      return newSSLContext()
        .apply {
          init(null, arrayOf<TrustManager>(trustManager), null)
        }.socketFactory
    } catch (e: GeneralSecurityException) {
      throw AssertionError("No System TLS: $e", e) // The system has no TLS. Just give up.
    }
  }

  override fun toString(): String = javaClass.simpleName

  companion object {
    @Volatile private var platform = findPlatform()

    // Helper to build a minimal smb URL
    private static URL smbUrl(String spec) {
        try {
            return new URL(null, spec, new Handler());
        } catch (MalformedURLException e) {
            throw new AssertionError("Failed to create SMB URL: " + spec, e);
        }
    }

    // Utility to build a minimal locator for connect tests
    private static SmbResourceLocatorImpl newLocator(CIFSContext ctx) {

  }

  private fun <T> finished(
    calls: Deque<T>,
    call: T,
  ) {
    val idleCallback: Runnable?
    synchronized(this) {
      if (!calls.remove(call)) throw AssertionError("Call wasn't in-flight!")
      idleCallback = this.idleCallback
    }

    val isRunning = promoteAndExecute()

    if (!isRunning && idleCallback != null) {
      idleCallback.run()
    }
  }

        override fun onResponse(
          call: Call,
          response: Response,
        ) {
          try {
            Thread.sleep(500)
          } catch (e: InterruptedException) {
            throw AssertionError()
          }
          assertFailsWith<IOException> {
            response.body.source().readUtf8()
          }.also { expected ->
            exceptionRef.set(expected)
            latch.countDown()

   */
  private static char[] growBuffer(char[] dest, int index, int size) {
    if (size < 0) { // overflow - should be OutOfMemoryError but GWT/j2cl don't support it
      throw new AssertionError("Cannot increase internal buffer any further");
    }
    char[] copy = new char[size];
    if (index > 0) {
      System.arraycopy(dest, 0, copy, 0, index);
    }
    return copy;
  }

    } catch (InvocationTargetException e) {
      if (exception != e.getCause()) {
        throw new RuntimeException(e);
      }
    } catch (IllegalAccessException e) {
      throw new AssertionError(e);
    }
  }

  private static <T> void testEquals(
      Class<T> interfaceType, Function<? super T, ? extends T> wrapperFunction) {
    FreshValueGenerator generator = new FreshValueGenerator();