* @since 18.0 (since 3.0 as {@code Objects.firstNonNull()}).
   */
  public static <T> T firstNonNull(@Nullable T first, @Nullable T second) {
    if (first != null) {
      return first;
    }
    if (second != null) {
      return second;
    }
    throw new NullPointerException("Both parameters are null");
  }

  /**
   * Creates an instance of {@link ToStringHelper}.
   *

		lookupHost = net.DefaultResolver.LookupHost
	}

	if baseDialCtx == nil {
		// This is same as which `http.DefaultTransport` uses.
		baseDialCtx = (&net.Dialer{
			Timeout:   30 * time.Second,
			KeepAlive: 30 * time.Second,
		}).DialContext
	}

	return func(ctx context.Context, network, addr string) (conn net.Conn, err error) {
		host, port, err := net.SplitHostPort(addr)
		if err != nil {
			return nil, err
		}

	// dRWMutexUnlockTimeout - default timeout for the unlock call
	drwMutexUnlockCallTimeout = 30 * time.Second

	// dRWMutexForceUnlockTimeout - default timeout for the unlock call
	drwMutexForceUnlockCallTimeout = 30 * time.Second

	// dRWMutexRefreshInterval - default the interval between two refresh calls
	drwMutexRefreshInterval = 10 * time.Second

	drwMutexInfinite = 1<<63 - 1
)

		}
		if _, err := io.WriteString(w.cw, h.Comment); err != nil {
			return err
		}
	}
	end := w.cw.count

	records := uint64(len(w.dir))
	size := uint64(end - start)
	offset := uint64(start)

	if f := w.testHookCloseSizeOffset; f != nil {
		f(size, offset)
	}

	if records >= uint16max || size >= uint32max || offset >= uint32max {
		var buf [directory64EndLen + directory64LocLen]byte
		b := writeBuf(buf[:])

 *   protected void visitWildcardType(WildcardType t) {
 *     throw new IllegalArgumentException("Cannot contain wildcard type.");
 *   }
 * }.visit(type);
 * }
 *
 * <p>One {@code Type} is visited at most once. The second time the same type is visited, it's
 * ignored by {@link #visit}. This avoids infinite recursion caused by recursive type bounds.
 *
 * <p>This class is not thread safe.
 *
 * @author Ben Yu
 */

  @CanIgnoreReturnValue
  public final <A extends Appendable> A appendTo(
      A appendable, @Nullable Object first, @Nullable Object second, @Nullable Object... rest)
      throws IOException {
    return appendTo(appendable, iterable(first, second, rest));
  }

  /**
   * Appends the string representation of each of {@code parts}, using the previously configured

    entry = cacheEntry1;
    if (entry != null && entry.key == key) {
      return entry.value;
    }
    entry = cacheEntry2;
    if (entry != null && entry.key == key) {
      // Promote second cache entry to first so the access pattern
      // [K1, K2, K1, K3, K1, K4...] still hits the cache half the time.
      addToCache(entry);
      return entry.value;
    }
    return null;
  }

  @Override

    builder.addEscape(' ', "-");
    builder.addEscape('!', "$");
    Escaper second = builder.build();
    // This should have no effect on existing escapers.
    builder.addEscape(' ', "*");

    // Test both escapers after modifying the builder.
    assertThat(first.escape("The Quick Brown Fox!")).isEqualTo("Xhe_Xuick_Xrown_XoxX");
    assertThat(second.escape("The Quick Brown Fox!")).isEqualTo("Xhe-Xuick-Xrown-Xox$");
  }

   * <a href="https://github.com/google/guava/wiki/CollectionUtilitiesExplained#comparators">{@code
   * Comparators}</a>.
   *
   * @param a first value to compare, returned if less than or equal to b.
   * @param b second value to compare.
   * @throws ClassCastException if the parameters are not <i>mutually comparable</i>.
   * @since 30.0
   */
  public static <T extends Comparable<? super T>> T min(T a, T b) {

	t.Run("testStreamRoundtrip", func(t *testing.T) {
		defer timeout(5 * time.Second)()
		testStreamRoundtrip(t, local, remote)
		assertNoActive(t, connRemoteLocal)
		assertNoActive(t, connLocalToRemote)
	})
	t.Run("testStreamCancel", func(t *testing.T) {
		defer timeout(5 * time.Second)()
		testStreamCancel(t, local, remote)
		assertNoActive(t, connRemoteLocal)