*
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  @SuppressWarnings({"unchecked"}) // fully variant implementation (never actually produces any Es)
  public static <E> ImmutableSet<E> of() {
    return (ImmutableSet<E>) RegularImmutableSet.EMPTY;
  }

  /**
   * Returns an immutable set containing {@code element}. Preferred over {@link

  // be a positive number. The server's concurrency limit (SCL) is
  // divided among the concurrency-controlled priority levels in
  // proportion to their assured concurrency shares. This produces
  // the assured concurrency value (ACV) --- the number of requests
  // that may be executing at a time --- for each such priority
  // level:
  //

  // be a positive number. The server's concurrency limit (SCL) is
  // divided among the concurrency-controlled priority levels in
  // proportion to their assured concurrency shares. This produces
  // the assured concurrency value (ACV) --- the number of requests
  // that may be executing at a time --- for each such priority
  // level:
  //

 * splitter can extract adjacent substrings of a given {@linkplain #fixedLength fixed length}.
 *
 * <p>For example, this expression:
 *
 * <pre>{@code
 * Splitter.on(',').split("foo,bar,qux")
 * }</pre>
 *
 * ... produces an {@code Iterable} containing {@code "foo"}, {@code "bar"} and {@code "qux"}, in
 * that order.
 *
 * <p>By default, {@code Splitter}'s behavior is simplistic and unassuming. The following
 * expression:
 *

 * splitter can extract adjacent substrings of a given {@linkplain #fixedLength fixed length}.
 *
 * <p>For example, this expression:
 *
 * <pre>{@code
 * Splitter.on(',').split("foo,bar,qux")
 * }</pre>
 *
 * ... produces an {@code Iterable} containing {@code "foo"}, {@code "bar"} and {@code "qux"}, in
 * that order.
 *
 * <p>By default, {@code Splitter}'s behavior is simplistic and unassuming. The following
 * expression:
 *

  // be a positive number. The server's concurrency limit (SCL) is
  // divided among the concurrency-controlled priority levels in
  // proportion to their assured concurrency shares. This produces
  // the assured concurrency value (ACV) --- the number of requests
  // that may be executing at a time --- for each such priority
  // level:
  //

		gotIdx = <-indexCh
		return gotIdx
	}
}

// compressSelfTest performs a self-test to ensure that compression
// algorithms completes a roundtrip. If any algorithm
// produces an incorrect checksum it fails with a hard error.
//
// compressSelfTest tries to catch any issue in the compression implementation
// early instead of silently corrupting data.
func compressSelfTest() {

   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  @SuppressWarnings({"unchecked"}) // fully variant implementation (never actually produces any Es)
  public static <E> ImmutableSet<E> of() {
    return (ImmutableSet<E>) RegularImmutableSet.EMPTY;
  }

  /**
   * Returns an immutable set containing {@code element}. Preferred over {@link

   *     is greater than the number of elements remaining in {@code iterator}
   * @return the element at the specified position in {@code iterator} or {@code defaultValue} if
   *     {@code iterator} produces fewer than {@code position + 1} elements.
   * @throws IndexOutOfBoundsException if {@code position} is negative
   * @since 4.0
   */
  @ParametricNullness
  public static <T extends @Nullable Object> T get(

      const std::function<void(BackwardFunction*)>& backward_function_deleter);

  void DeleteTrace(int64_t tensor_id);

  // Consumes the internal state of the tape (so cannot be called more than
  // once) and produces the gradient of the target tensors with respect to the
  // source tensors. The output gradients are used if not empty and not
  // null. The result is populated with one tensor per target element.