_2019-06-21_

 *  New: Require Kotlin 1.3.40.
 *  New: Change the Kotlin API from `File.toRequestBody()` to `File.asRequestBody()` and
    `BufferedSource.toResponseBody()` to `BufferedSource.asResponseBody()`. If the returned value
    is a view of what created it, we use _as_.
 *  Fix: Permit response codes of zero for compatibility with OkHttp 3.x.
 *  Fix: Change the return type of `MockWebServer.takeRequest()` to be nullable.

 * of which connections to keep open for future use.
 *
 * @constructor Create a new connection pool with tuning parameters appropriate for a single-user
 * application. The tuning parameters in this pool are subject to change in future OkHttp releases.
 * Currently this pool holds up to 5 idle connections which will be evicted after 5 minutes of
 * inactivity.
 */
class ConnectionPool internal constructor(

 * [application interceptor][OkHttpClient.interceptors] or as a [OkHttpClient.networkInterceptors].
 *
 * The format of the logs created by this class should not be considered stable and may
 * change slightly between releases. If you need a stable logging format, use your own interceptor.
 */
class HttpLoggingInterceptor
  @JvmOverloads
  constructor(
    private val logger: Logger = Logger.DEFAULT,

  }

  /**
   * Duplex calls that have follow-ups are weird. By the time we know there's a follow-up we've
   * already split off another thread to stream the request body. Because we permit at most one
   * exchange at a time we break the request stream out from under that writer.
   */
  @Test
  fun duplexWithRedirect() {
    enableProtocol(Protocol.HTTP_2)
    val duplexResponseSent = CountDownLatch(1)
    listener =

      val source = raw.source().buffer()
      val sink = raw.sink().buffer()
      while (true) {
        val socketStillGood = processOneRequest(raw, source, sink)

        // Clean up after the last exchange on a socket.
        if (!socketStillGood) {
          raw.close()
          openClientSockets.remove(raw)
          return false
        }

  /**
   * Cancel this stream. Resources held by this stream will be cleaned up, though not synchronously.
   * That may happen later by the connection pool thread.
   */
  fun cancel()

  /**
   * Carries an exchange. This is usually a connection, but it could also be a connect plan for
   * CONNECT tunnels. Note that CONNECT tunnels are significantly less capable than connections.
   */
  interface Carrier {
    val route: Route

  return charset to finalContentType
}

internal fun MediaType?.charsetOrUtf8(): Charset {
  return this?.charset() ?: Charsets.UTF_8
}

internal val Response.connection: RealConnection
  get() = this.exchange!!.connection

internal fun OkHttpClient.Builder.taskRunnerInternal(taskRunner: TaskRunner) = this.taskRunner(taskRunner)

internal fun buildConnectionPool(
  connectionListener: ConnectionListener,

 * [connection pool][ConnectionPool].
 *
 * Do not confuse this class with the misnamed `HttpURLConnection`, which isn't so much a connection
 * as a single request/response exchange.
 *
 * ## Modern TLS
 *
 * There are trade-offs when selecting which options to include when negotiating a secure connection
 * to a remote host. Newer TLS options are quite useful:
 *

   * provides support.
   */
  QUIC("quic"),

  /**
   * HTTP/3 is the third and upcoming major version of the Hypertext Transfer Protocol used to
   * exchange information. HTTP/3 runs over QUIC, which is published as RFC 9000.
   *
   * HTTP/3 is not natively supported by OkHttp, but provided to allow a theoretical interceptor
   * that provides support.
   */
  HTTP_3("h3"),

```java
HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
logging.setLevel(Level.BASIC);
OkHttpClient client = new OkHttpClient.Builder()
  .addInterceptor(logging)
  .build();
```

You can change the log level at any time by calling `setLevel()`.

To log to a custom location, pass a `Logger` instance to the constructor.
```java
HttpLoggingInterceptor logging = new HttpLoggingInterceptor(new Logger() {