public void testToOptionalEmpty() {
    assertThat(Stream.empty().collect(toOptional())).isEmpty();
  }

  public void testToOptionalSingleton() {
    assertThat(Stream.of(1).collect(toOptional())).hasValue(1);
  }

  public void testToOptionalNull() {
    Stream<@Nullable Object> stream = Stream.of((Object) null);
    assertThrows(NullPointerException.class, () -> stream.collect(toOptional()));
  }

  /**
   * Performs a {@linkplain java.lang.invoke.VarHandle#compareAndSet compare-and-set} operation on
   * {@link #valueField} of {@code future}.
   */
  static boolean casValue(AbstractFutureState<?> future, @Nullable Object expect, Object update) {
    return ATOMIC_HELPER.casValue(future, expect, update);
  }

  /** Returns the value of the future, using a volatile read. */
  final @Nullable Object value() {
    return valueField;
  }

        String value = null;
        boolean haveValue = false;
        if (encoding != null) {
            try {
                value = item.getString(encoding);
                haveValue = true;
            } catch (final Exception e) {}
        }
        if (!haveValue) {
            try {
                value = item.getString(Charset.forName("ISO-8859-1"));

      if (owner.value() != this) {
        // nothing to do, we must have been cancelled, don't bother inspecting the future.
        return;
      }
      Object valueToSet = getFutureValue(future);
      if (casValue(owner, this, valueToSet)) {
        complete(
            owner,
            /*
             * Interruption doesn't propagate through a DelegatingToFuture chain (see

      return true;
    }
    return false;
  }

  final @Nullable Listener gasListeners(Listener update) {
    Listener old = listeners;
    listeners = update;
    return old;
  }

  static boolean casValue(AbstractFutureState<?> future, @Nullable Object expect, Object update) {
    if (future.value == expect) {
      future.value = update;
      return true;
    }
    return false;
  }

  }

  public void testTryFind() {
    Iterable<String> list = newArrayList("cool", "pants");
    assertThat(tryFind(list, equalTo("cool"))).hasValue("cool");
    assertThat(tryFind(list, equalTo("pants"))).hasValue("pants");
    assertThat(tryFind(list, Predicates.alwaysTrue())).hasValue("cool");
    assertThat(tryFind(list, Predicates.alwaysFalse())).isAbsent();
    assertCanIterateAgain(list);
  }

        @SuppressWarnings({"unchecked", "nullness"})
        K castKey = (K) key;
        @SuppressWarnings({"unchecked", "nullness"}) // similar to the above
        V castValue = (V) value;

        alertListenerIfPresent(castKey, castValue, RemovalCause.EXPLICIT);
        remove(key);
        return true;
      }
      return false;
    }
  }

  @Override

    Iterator<String> iterator = list.iterator();
    assertThat(tryFind(iterator, equalTo("cool"))).hasValue("cool");
  }

  public void testTryFind_lastElement() {
    Iterable<String> list = Lists.newArrayList("cool", "pants");
    Iterator<String> iterator = list.iterator();
    assertThat(tryFind(iterator, equalTo("pants"))).hasValue("pants");
  }

  public void testTryFind_alwaysTrue() {

     * anything that might slow down execution on such a hot path. Given that the methods are only
     * package-private, I feel OK with just not testing them for NPE.
     *
     * Note that testing casValue is particularly dangerous because it uses Unsafe under some
     * versions of Java, and apparently Unsafe can cause SIGSEGV instead of NPE—almost as if it's
     * not safe.
     */
    concat(

  DLManagedTensor* dlmt = static_cast<DLManagedTensor*>(dlm);
  DLTensor* dl_tensor = &dlmt->dl_tensor;
  absl::optional<std::string> device_name =
      DeviceNameFromDlContext(dl_tensor->device, status);
  if (!device_name.has_value()) {
    status->status =
        tensorflow::errors::InvalidArgument("Unsupported Device Type");
    return nullptr;
  }
  TF_DataType dtype;
  absl::Status s = TfDataTypeFormDlDataType(dl_tensor->dtype, &dtype);