* https, etc.) of the URL, not the protocol (http/1.1, spdy/3.1, etc.). OkHttp uses the word
 * *protocol* to identify how HTTP messages are framed.
 *
 * [ietf_alpn]: http://tools.ietf.org/html/draft-ietf-tls-applayerprotoneg
 */
enum class Protocol(
  private val protocol: String,
) {
  /**
   * An obsolete plaintext framing that does not use persistent sockets by default.
   */
  HTTP_1_0("http/1.0"),

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.internal.http2

/** http://tools.ietf.org/html/draft-ietf-httpbis-http2-17#section-7 */
enum class ErrorCode constructor(
  val httpCode: Int,
) {
  /** Not an error!  */
  NO_ERROR(0),

  PROTOCOL_ERROR(1),

  INTERNAL_ERROR(2),

* HTTP Semantics - [RFC 9110](https://datatracker.ietf.org/doc/html/rfc9110)
* HTTP Caching- [RFC 9111](https://datatracker.ietf.org/doc/html/rfc9111)
* HTTP/1.1 - [RFC 9112](https://datatracker.ietf.org/doc/html/rfc9112)
* HTTP/2 - [RFC 9113](https://datatracker.ietf.org/doc/html/rfc9113)
* Websockets - [RFC 6455](https://datatracker.ietf.org/doc/html/rfc6455)

    }
  }

  companion object {
    /**
     * The cipher suite used during TLS connection fallback to indicate a fallback. See
     * https://tools.ietf.org/html/draft-ietf-tls-downgrade-scsv-00
     */
    const val TLS_FALLBACK_SCSV = "TLS_FALLBACK_SCSV"
  }

 *
 * The current implementation does not address any of:
 *  - Async DNS split by IP class
 *  - Stateful handling of connectivity results
 *  - The prioritisation of addresses
 *
 * https://datatracker.ietf.org/doc/html/rfc8305#section-4
 */
internal fun reorderForHappyEyeballs(addresses: List<InetAddress>): List<InetAddress> {
  if (addresses.size < 2) {
    return addresses
  }

 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package okhttp3.internal.http

// HTTP Status Codes not offered by HttpUrlConnection.
//
// https://datatracker.ietf.org/doc/html/rfc7231#page-47
//
// From https://github.com/apache/httpcomponents-core/blob/master/httpcore5/src/main/java/org/apache/hc/core5/http/HttpStatus.java

/** `100 Continue` (HTTP/1.1 - RFC 7231)  */

 * database to hold accepted cookies. The [cookie storage model][rfc_6265_53] specifies policies for
 * updating and expiring cookies.
 *
 * [rfc_6265_53]: https://tools.ietf.org/html/rfc6265#section-5.3
 */
interface CookieJar {
  /**
   * Saves [cookies] from an HTTP response to this store according to this jar's policy.
   *

import okio.Buffer
import okio.BufferedSink
import okio.ByteString

/**
 * An [RFC 6455][rfc_6455]-compatible WebSocket frame writer.
 *
 * This class is not thread safe.
 *
 * [rfc_6455]: http://tools.ietf.org/html/rfc6455
 */
class WebSocketWriter(
  private val isClient: Boolean,
  val sink: BufferedSink,
  val random: Random,
  private val perMessageDeflate: Boolean,
  private val noContextTakeover: Boolean,

    private const val TRANSFER_ENCODING = "transfer-encoding"
    private const val TE = "te"
    private const val ENCODING = "encoding"
    private const val UPGRADE = "upgrade"

    /** See http://tools.ietf.org/html/draft-ietf-httpbis-http2-09#section-8.1.3. */
    private val HTTP_2_SKIPPED_REQUEST_HEADERS =
      immutableListOf(
        CONNECTION,
        HOST,
        KEEP_ALIVE,
        PROXY_CONNECTION,
        TE,

 *   int result = 1;
 *   while ((response = response.priorResponse()) != null) {
 *     result++;
 *   }
 *   return result;
 * }
 * ```
 *
 * [1]: https://tools.ietf.org/html/rfc2817
 */
fun interface Authenticator {
  /**
   * Returns a request that includes a credential to satisfy an authentication challenge in
   * [response]. Returns null if the challenge cannot be satisfied.