* absent, it will fall back to a heavyweight operation that will open a stream, read (or {@link
   * InputStream#skip(long) skip}, if possible) to the end of the stream and return the total number
   * of bytes that were read.
   *
   * <p>Note that for some sources that implement {@link #sizeIfKnown} to provide a more efficient
   * implementation, it is <i>possible</i> that this method will return a different number of bytes

        }
      }
    }
  }

  private void waitForInterrupt(Thread currentThread) {
    /*
     * If someone called cancel(true), it is possible that the interrupted bit hasn't been set yet.
     * Wait for the interrupting thread to set DONE. (See interruptTask().) We want to wait so that
     * the interrupting thread doesn't interrupt the _next_ thing to run on this thread.
     *

  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNullPointers() {
    /*
     * Don't bother testing: Preconditions defines a bunch of methods that accept a template (or
     * even entire message) that simultaneously:
     *
     * - _shouldn't_ be null, so we don't annotate it with @Nullable
     *
     * - _can_ be null without causing a runtime failure (because we don't want the interesting

      assertTrue(burst <= 1000);
      long afterBurst = measureTotalTimeMillis(limiter, oneSecWorthOfWork, new Random());
      // but work beyond that must take at least one second
      assertTrue(afterBurst >= 1000);
    }
  }

  /**
   * This neat test shows that no matter what weights we use in our requests, if we push X amount of
   * permits in a cool state, where X = rate * timeToCoolDown, and we have specified a

   *
   * <ol>
   *   <li>Use sendfile(2) or equivalent. Requires that both the input channel and the output
   *       channel have their own file descriptors. Generally this only happens when both channels
   *       are files or sockets. This performs zero copies - the bytes never enter userspace.
   *   <li>Use mmap(2) or equivalent. Requires that either the input channel or the output channel

    }
  }

  /*
   * Whenever an implementation uses `instanceof` on a parameter instance, the test has to know that
   * (so much for "black box") and try instances that both do and don't pass the check. The "don't"
   * half of that is more awkward to arrange...
   */
  private static <T> Iterable<T> iterable(final Collection<T> collection) {
    // return collection::iterator;

      list.add(new Object());
    }

    Ordering<Object> arbitrary = Ordering.arbitrary();
    Collections.sort(list, arbitrary);

    // Now we don't care what order it's put the list in, only that
    // comparing any pair of elements gives the answer we expect.
    Helpers.testComparator(arbitrary, list);

    assertEquals("Ordering.arbitrary()", arbitrary.toString());
  }

  @J2ktIncompatible // ArbitraryOrdering

      list.add(new Object());
    }

    Ordering<Object> arbitrary = Ordering.arbitrary();
    Collections.sort(list, arbitrary);

    // Now we don't care what order it's put the list in, only that
    // comparing any pair of elements gives the answer we expect.
    Helpers.testComparator(arbitrary, list);

    assertEquals("Ordering.arbitrary()", arbitrary.toString());
  }

  @J2ktIncompatible // ArbitraryOrdering

   * that use {@code comparator} to determine the least and greatest elements.
   */
  /*
   * TODO(cpovirk): Change to Comparator<? super B> to permit Comparator<@Nullable ...> and
   * Comparator<SupertypeOfB>? What we have here matches the immutable collections, but those also
   * expose a public Builder constructor that accepts "? super." So maybe we should do *that*
   * instead.
   */

    }
  }

  /*
   * Whenever an implementation uses `instanceof` on a parameter instance, the test has to know that
   * (so much for "black box") and try instances that both do and don't pass the check. The "don't"
   * half of that is more awkward to arrange...
   */
  private static <T> Iterable<T> iterable(final Collection<T> collection) {
    // return collection::iterator;