go c.monitorState(conn, cancel)

	c.handleMsgWg.Add(2)
	c.reconnectMu.Unlock()

	// Start reader and writer
	go c.readStream(ctx, conn, cancel)
	c.writeStream(ctx, conn, cancel)
}

// readStream handles the read side of the connection.
// It will read messages and send them to c.handleMsg.
// If an error occurs the cancel function will be called and conn be closed.

 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 

    assertEquals(0x9999999999999999L, HashCode.fromBytesNoCopy(byteArrayWith9s(8)).padToLong());
  }

  private static byte[] byteArrayWith9s(int size) {
    byte[] bytez = new byte[size];
    Arrays.fill(bytez, (byte) 0x99);
    return bytez;
  }

  public void testToString() {
    byte[] data = new byte[] {127, -128, 5, -1, 14};
    assertEquals("7f8005ff0e", HashCode.fromBytes(data).toString());

 * including dots after the first colon. It matches IPv4 addresses as strings containing only
 * decimal digits and dots. This pattern matches strings like "a:.23" and "54" that are neither IP
 * addresses nor hostnames; they will be verified as IP addresses (which is a more strict
 * verification).
 */
private val VERIFY_AS_IP_ADDRESS = "([0-9a-fA-F]*:[0-9a-fA-F:.]*)|([\\d.]+)".toRegex()

type xlMetaV2 struct {
	versions []xlMetaV2ShallowVersion

	// data will contain raw data if any.
	// data will be one or more versions indexed by versionID.
	// To remove all data set to nil.
	data xlMetaInlineData

	// metadata version.
	metaV uint8
}

// LoadOrConvert will load the metadata in the buffer.
// If this is a legacy format, it will automatically be converted to XLV2.

   * Unicode 6.0. Note that this is a stronger criterion than simply whether the bytes can be
   * decoded. For example, some versions of the JDK decoder will accept "non-shortest form" byte
   * sequences, but encoding never reproduces these. Such byte sequences are <i>not</i> considered
   * well-formed.
   *

 * degrades more gracefully for worst-case input.
 *
 * <p>The implementation does not necessarily use a <i>stable</i> sorting algorithm; when multiple
 * equivalent elements are added to it, it is undefined which will come first in the output.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class TopKSelector<
    T extends @Nullable Object> {

  /**

func (s *scratch) add(c byte) {
	if s.fill+1 >= cap(s.data) {
		s.grow()
	}

	s.data[s.fill] = c
	s.fill++
}

// append encoded rune to scratch buffer
func (s *scratch) addRune(r rune) int {
	if s.fill+utf8.UTFMax >= cap(s.data) {
		s.grow()
	}

	n := utf8.EncodeRune(s.data[s.fill:], r)
	s.fill += n
	return n

// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//

<img src="/img/tutorial/separate-openapi-schemas/image02.png">
</div>

This means that it will **always have a value**, it's just that sometimes the value could be `None` (or `null` in JSON).

That means that, clients using your API don't have to check if the value exists or not, they can **assume the field will always be there**, but just that in some cases it will have the default value of `None`.