}

  /**
   * Returns a serializable converter object that converts between strings and longs using {@link
   * Long#decode} and {@link Long#toString()}. The returned converter throws {@link
   * NumberFormatException} if the input string is invalid.
   *
   * <p><b>Warning:</b> please see {@link Long#decode} to understand exactly how strings are parsed.

    The summary is that it ignores one file in favor of the other.
    util.concurrent, like nearly all our packages, has two .gwt.xml files: one
    for prod and one for tests. However, unlike our other packages, as of this
    writing it has test supersource but no prod supersource.

    GWT happens to use the prod .gwt.xml, so it looks for no supersource for

    The summary is that it ignores one file in favor of the other.
    util.concurrent, like nearly all our packages, has two .gwt.xml files: one
    for prod and one for tests. However, unlike our other packages, as of this
    writing it has test supersource but no prod supersource.

    GWT happens to use the prod .gwt.xml, so it looks for no supersource for

    The summary is that it ignores one file in favor of the other.
    util.concurrent, like nearly all our packages, has two .gwt.xml files: one
    for prod and one for tests. However, unlike our other packages, as of this
    writing it has test supersource but no prod supersource.

    GWT happens to use the prod .gwt.xml, so it looks for no supersource for

    The summary is that it ignores one file in favor of the other.
    util.concurrent, like nearly all our packages, has two .gwt.xml files: one
    for prod and one for tests. However, unlike our other packages, as of this
    writing it has test supersource but no prod supersource.

    GWT happens to use the prod .gwt.xml, so it looks for no supersource for

    The summary is that it ignores one file in favor of the other.
    util.concurrent, like nearly all our packages, has two .gwt.xml files: one
    for prod and one for tests. However, unlike our other packages, as of this
    writing it has test supersource but no prod supersource.

    GWT happens to use the prod .gwt.xml, so it looks for no supersource for

  }

  /*
   * If I understand correctly:
   *
   * This needs to be a @JsMethod so that J2CL knows to look for a JavaScript implemention of
   * it in Platform.native.js. (The JavaScript implementation inline below is visible to *GWT*, but
   * *J2CL* doesn't look at it.)
   *
   * However, once it's a @JsMethod, GWT produces a warning. That's because (a) the *other* purpose

    }
    return handleInvocation(proxy, method, args);
  }

  /**
   * {@link #invoke} delegates to this method upon any method invocation on the proxy instance,
   * except {@link Object#equals}, {@link Object#hashCode} and {@link Object#toString}. The result
   * will be returned as the proxied method's return value.
   *
   * <p>Unlike {@link #invoke}, {@code args} will never be null. When the method has no parameter,

  private static final HashFunction SIP_WITHOUT_KEY = Hashing.sipHash24();

  // These constants were originally ported from https://www.131002.net/siphash/siphash24.c. See:
  // https://github.com/nahi/siphash-java-inline/blob/master/src/test/java/org/jruby/util/SipHashInlineTest.java
  private static final long[] EXPECTED =
      new long[] {
        0x726fdb47dd0e0e31L,
        0x74f839c593dc67fdL,
        0x0d6c8009d9a94f5aL,

    } else {
      return ((Comparator<@Nullable Object>) comparator).compare(o1, o2);
    }
  }

  /**
   * A sensible definition of {@link #containsKey} in terms of the {@code firstKey()} method of
   * {@link #tailMap}. If you override {@link #tailMap}, you may wish to override {@link
   * #containsKey} to forward to this implementation.
   *
   * @since 7.0
   */
  @Override