seenExceptionsLocal = newConcurrentHashSet();
      /*
       * Other handleException() callers may see this as soon as we publish it. We need to populate
       * it with the initial failure before we do, or else they may think that the initial failure
       * has never been seen before.
       */
      addInitialException(seenExceptionsLocal);

      ATOMIC_HELPER.compareAndSetSeenExceptions(this, null, seenExceptionsLocal);
      /*

  public static void startFinalizer(
      Class<?> finalizableReferenceClass,
      ReferenceQueue<Object> queue,
      PhantomReference<Object> frqReference) {
    /*
     * We use FinalizableReference.class for two things:
     *
     * 1) To invoke FinalizableReference.finalizeReferent()
     *
     * 2) To detect when FinalizableReference's class loader has to be garbage collected, at which
     * point, Finalizer can stop running

      boolean isPossibleChainingCall = interfaceType.isAssignableFrom(method.getReturnType());
      try {
        Object actualReturnValue = method.invoke(wrapper, passedArgs);
        // If we think this might be a 'chaining' call then we allow the return value to either
        // be the wrapper or the returnValue.
        if (!isPossibleChainingCall || wrapper != actualReturnValue) {
          assertEquals(

      .build()
    assertThat(original.interceptors.size).isEqualTo(0)
    assertThat(original.networkInterceptors.size).isEqualTo(0)
  }

  /**
   * When copying the client, stateful things like the connection pool are shared across all
   * clients.
   */
  @Test fun cloneSharesStatefulInstances() {
    val client = clientTestRule.newClient()

    // Values should be non-null.

      boolean isPossibleChainingCall = interfaceType.isAssignableFrom(method.getReturnType());
      try {
        Object actualReturnValue = method.invoke(wrapper, passedArgs);
        // If we think this might be a 'chaining' call then we allow the return value to either
        // be the wrapper or the returnValue.
        if (!isPossibleChainingCall || wrapper != actualReturnValue) {
          assertEquals(

  `Headers.of(String...)` with `headersOf(vararg String)`.

#### Extension Functions

We’ve migrated from static functions to extension functions where we think they fit.

| Java                                | Kotlin                          |
| :---------------------------------- | :------------------------------ |

So, in our example, we can make `tags` be specifically a "list of strings":

{* ../../docs_src/body_nested_models/tutorial002_py310.py hl[12] *}

## Set types { #set-types }

But then we think about it, and realize that tags shouldn't repeat, they would probably be unique strings.

And Python has a special data type for sets of unique items, the `set`.

Then we can declare `tags` as a set of strings:

         * same—hence the try-catch here.
         *
         * (Really, we're fortunate that breaking AtomicReferenceFieldUpdater doesn't break _even
         * more_ things.)
         */
        helper = new SynchronizedHelper();
      }
    }
    ATOMIC_HELPER = helper;

    // Prevent rare disastrous classloading in first call to LockSupport.park.

   */
  // Note: 90% of the time we don't add type parameters or wildcards that serve only to "tweak" the
  // desired return type. However, *nested* generics introduce a special class of problems that we
  // think tip it over into being worthwhile.
  public static <T extends @Nullable Object, S extends T> Comparator<Iterable<S>> lexicographical(
      Comparator<T> comparator) {

     */
    static final VarHandle HANDLE = byteArrayViewVarHandle(long[].class, LITTLE_ENDIAN);
  }

  /**
   * The only reference to Unsafe is in this nested class. We set things up so that if
   * Unsafe.theUnsafe is inaccessible, the attempt to load the nested class fails, and the outer
   * class's static initializer can fall back on a non-Unsafe version.
   */