}
      } while ((byte1 = bytes[index++]) >= 0);

      if (byte1 < (byte) 0xE0) {
        // Two-byte form.
        if (index == end) {
          return false;
        }
        // Simultaneously check for illegal trailing-byte in leading position
        // and overlong 2-byte form.
        if (byte1 < (byte) 0xC2 || bytes[index++] > (byte) 0xBF) {
          return false;
        }

        }
      } while ((byte1 = bytes[index++]) >= 0);

      if (byte1 < (byte) 0xE0) {
        // Two-byte form.
        if (index == end) {
          return false;
        }
        // Simultaneously check for illegal trailing-byte in leading position
        // and overlong 2-byte form.
        if (byte1 < (byte) 0xC2 || bytes[index++] > (byte) 0xBF) {
          return false;
        }

  @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

 * is intended solely to help find problems during development.
 *
 * <p>The EventBus guarantees that it will not call a subscriber method from multiple threads
 * simultaneously, unless the method explicitly allows it by bearing the {@link
 * AllowConcurrentEvents} annotation. If this annotation is not present, subscriber methods need not

  @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

        // this can be safely acquired after the acquiredLock.
        //
        // Note that there is a race condition here which can result in missing
        // a cyclic edge: it's possible for two threads to simultaneous find
        // "safe" edges which together form a cycle. Preventing this race
        // condition efficiently without _introducing_ deadlock is probably

    cache.put(key, "1");
    // simultaneous update for same key, some null, some non-null
    doParallelCacheOp(
        count,
        n -> {
          cache.asMap().compute(key, (k, v) -> n % 2 == 0 ? v + delimiter + n : null);
        });
    assertTrue(1 >= cache.size());
  }

  public void testCompute() {
    cache.put(key, "1");
    // simultaneous deletion
    doParallelCacheOp(
        count,