)

// metadata stream format:
//
// The stream is s2 compressed.
// https://github.com/klauspost/compress/tree/master/s2#s2-compression
// This ensures integrity and reduces the size typically by at least 50%.
//
// All stream elements are msgpack encoded.
//
// 1 Integer, metacacheStreamVersion of the writer.
// This can be used for managing breaking changes.
//
// For each element:

 *   <li><b>Null-hostility.</b> This collection will never contain a null element.
 *   <li><b>Deterministic iteration.</b> The iteration order is always well-defined, depending on
 *       how the collection was created. Typically this is insertion order unless an explicit
 *       ordering is otherwise specified (e.g. {@link ImmutableSortedSet#naturalOrder}). See the
 *       appropriate factory method for details. View collections such as {@link

    of the contribution must be compared against the cost of maintaining the
    feature.
*   Full new features (e.g., a new op implementing a cutting-edge algorithm)
    typically will live in
    [tensorflow/addons](https://github.com/tensorflow/addons) to get some
    airtime before a decision is made regarding whether they are to be migrated
    to the core.

 *       instance each time they are called. The caller is responsible for ensuring that the
 *       returned reader is closed.
 *   <li><b>Convenience methods:</b> These are implementations of common operations that are
 *       typically implemented by opening a reader using one of the methods in the first category,
 *       doing something and finally closing the reader that was opened.
 * </ul>
 *

 *       instance each time they are called. The caller is responsible for ensuring that the
 *       returned reader is closed.
 *   <li><b>Convenience methods:</b> These are implementations of common operations that are
 *       typically implemented by opening a reader using one of the methods in the first category,
 *       doing something and finally closing the reader that was opened.
 * </ul>
 *

   *   Long.MIN_VALUE or Long.MAX_VALUE.
   * - Favor responding to interrupts over timeouts.
   * - System.nanoTime() is expensive enough that we want to call it the minimum required number of
   *   times, typically once before invoking a blocking method. This often requires keeping track of
   *   the first time in a method that nanoTime() has been invoked, for which the special value 0L

       * (We also haven't benchmarked under Android. We continue to use UnsafeAtomicHelper there so
       * that we don't change the performance there, for better or for worse.) Fortunately, JVM
       * users will typically use guava-jre, not guava-android, and guava-jre uses the VarHandle
       * implementation when possible.
       */
      try {
        helper = new AtomicReferenceFieldUpdaterAtomicHelper();

      /**
       * The service that is managing this callable. This is used so that failure can be reported
       * properly.
       */
      /*
       * This reference is part of a reference cycle, which is typically something we want to avoid
       * under j2objc -- but it is not detected by our j2objc cycle test. The cycle:
       *
       * - CustomScheduler.service contains an instance of ServiceDelegate. (It needs it so that it

   *
   * <p>These functions will never be passed {@code null} and must not under any circumstances
   * return {@code null}. If a value cannot be converted, the function should throw an unchecked
   * exception (typically, but not necessarily, {@link IllegalArgumentException}).
   *
   * <p>The returned converter is serializable if both provided functions are.
   *
   * @since 17.0
   */
  public static <A, B> Converter<A, B> from(

      /**
       * The service that is managing this callable. This is used so that failure can be reported
       * properly.
       */
      /*
       * This reference is part of a reference cycle, which is typically something we want to avoid
       * under j2objc -- but it is not detected by our j2objc cycle test. The cycle:
       *
       * - CustomScheduler.service contains an instance of ServiceDelegate. (It needs it so that it