* @return this for the builder pattern
   */
  @CanIgnoreReturnValue
  public ThreadFactoryBuilder setNameFormat(String nameFormat) {
    String unused = format(nameFormat, 0); // fail fast if the format is bad or null
    this.nameFormat = nameFormat;
    return this;
  }

  /**
   * Sets daemon or not for new threads created with this ThreadFactory.
   *

  /*
   * Abstract methods from Writer
   */

  @Override
  public void write(char[] cbuf, int off, int len) throws IOException {
    checkNotClosed();
    // It turns out that creating a new String is usually as fast, or faster
    // than wrapping cbuf in a light-weight CharSequence.
    target.append(new String(cbuf, off, len));
  }

  /*
   * Override a few functions for performance reasons to avoid creating unnecessary strings.

   *
   * @throws ClassCastException if the cause cannot be cast to the expected type. The {@code
   *     ClassCastException}'s cause is {@code throwable}.
   * @since 22.0
   */
  @GwtIncompatible // Class.cast(Object)
  public static <X extends Throwable> @Nullable X getCauseAs(
      Throwable throwable, Class<X> expectedCauseType) {
    try {
      return expectedCauseType.cast(throwable.getCause());
    } catch (ClassCastException e) {

   * - https://github.com/jspecify/jspecify/issues/65
   *
   * - https://github.com/jspecify/jdk/commit/71d826792b8c7ef95d492c50a274deab938f2552
   */
  /*
   * TODO(cpovirk): Is the unchecked cast avoidable? Would System.arraycopy be similarly fast (if
   * likewise not type-checked)? Could our single caller do something different?
   */
  @SuppressWarnings({"nullness", "unchecked"})

      - name: Run native-image tests
        run: ./gradlew -PgraalBuild=true native-image-tests:nativeTest

  testandroid:
    runs-on: ubuntu-latest
    timeout-minutes: 30

    strategy:
      fail-fast: false
      matrix:
        api-level:
          - 21
          - 29
          - 34

    steps:
      - name: Checkout
        uses: actions/checkout@v5

      - name: Configure JDK

   * - https://github.com/jspecify/jspecify/issues/65
   *
   * - https://github.com/jspecify/jdk/commit/71d826792b8c7ef95d492c50a274deab938f2552
   */
  /*
   * TODO(cpovirk): Is the unchecked cast avoidable? Would System.arraycopy be similarly fast (if
   * likewise not type-checked)? Could our single caller do something different?
   */
  @SuppressWarnings({"nullness", "unchecked"})

       * AGP: https://github.com/google/guava/issues/7769.
       *
       * My impression is that an AtomicReferenceFieldUpdater in a static field is similarly fast to
       * Unsafe on modern JVMs (if perhaps not quite as fast as VarHandle?). However, I'm not sure
       * exactly what we've benchmarked, and we certainly haven't benchmarked as far back as JDK 8.

      if (spinCount > MAX_BUSY_WAIT_SPINS) {
        /*
         * If we have spun a lot, just park ourselves. This will save CPU while we wait for a slow
         * interrupting thread. In theory, interruptTask() should be very fast, but due to
         * InterruptibleChannel and JavaLangAccess.blockedOn(Thread, Interruptible), it isn't
         * predictable what work might be done. (e.g., close a file and flush buffers to disk). To

        return sqrtFloor;
      case CEILING:
      case UP:
        int sqrtFloorInt = sqrtFloor.intValue();
        boolean sqrtFloorIsExact =
            (sqrtFloorInt * sqrtFloorInt == x.intValue()) // fast check mod 2^32
                && sqrtFloor.pow(2).equals(x); // slow exact check
        return sqrtFloorIsExact ? sqrtFloor : sqrtFloor.add(BigInteger.ONE);
      case HALF_DOWN:
      case HALF_UP:

          x >>>= shift;
        } while (x != 0);
      } else {
        // Separate off the last digit using unsigned division. That will leave
        // a number that is nonnegative as a signed integer.
        long quotient;
        if ((radix & 1) == 0) {
          // Fast path for the usual case where the radix is even.
          quotient = (x >>> 1) / (radix >>> 1);
        } else {