client =
      OkHttpClient
        .Builder()
        .connectionPool(client.connectionPool)
        .proxy(server.proxyAddress)
        .build()
    executeSynchronously("/a").assertBody("abc")
    client =
      OkHttpClient
        .Builder()
        .connectionPool(client.connectionPool)
        .proxy(server.proxyAddress)
        .build()

      builder.eventListenerFactory(LoggingEventListener.Factory(logger))
    }
    return builder.build()
  }

  fun close() {
    val okHttpClient = client as OkHttpClient
    okHttpClient.connectionPool.evictAll() // Close any persistent connections.
    okHttpClient.dispatcher.executorService.shutdownNow()
  }

  companion object {
    internal const val NAME = "okcurl"

   serverSocketFactory
 * **MultipartBody.Part**: body, headers
 * **MultipartBody.**: boundary, parts, size, type
 * **OkHttpClient**: authenticator, cache, callTimeoutMillis, certificatePinner,
   connectTimeoutMillis, connectionPool, connectionSpecs, cookieJar, dispatcher, dns,
   eventListenerFactory, followRedirects, followSslRedirects, hostnameVerifier, interceptors,

        Thread.sleep(1000)
        sendTestRequest(twitterRequest)
        Thread.sleep(1000)
        sendTestRequest(googleRequest)
        Thread.sleep(2000)
      }
    } finally {
      client.connectionPool.evictAll()
      client.dispatcher.executorService.shutdownNow()

      if (launch == CommandLine) {
        process?.destroyForcibly()
      }
    }
  }

TCP socket connection. Sharing a connection has substantial performance benefits: lower latency, higher throughput (due to [TCP slow start](https://www.igvita.com/2011/10/20/faster-web-vs-tcp-slow-start/)) and conserved battery. OkHttp uses a [ConnectionPool](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-connection-pool/) that automatically reuses HTTP/1.x connections and multiplexes HTTP/2 connections.

In OkHttp some fields of the address come from the URL (scheme, hostname, port)...

	public final fun certificatePinner ()Lokhttp3/CertificatePinner;
	public final fun connectTimeoutMillis ()I
	public final fun connectionPool ()Lokhttp3/ConnectionPool;
	public final fun connectionSpecs ()Ljava/util/List;
	public final fun cookieJar ()Lokhttp3/CookieJar;
	public final fun dispatcher ()Lokhttp3/Dispatcher;
	public final fun dns ()Lokhttp3/Dns;

    val hostnameVerifier = RecordingHostnameVerifier()
    val cookieJar: CookieJar = JavaNetCookieJar(CookieManager())
    val connectionPool = ConnectionPool()
    client =
      OkHttpClient
        .Builder()
        .cache(cache)
        .connectionPool(connectionPool)
        .cookieJar(cookieJar)
        .sslSocketFactory(clientSocketFactory, handshakeCertificates.trustManager)

      )
    val response1 = call1.execute()
    assertThat(response1.body.string()).isEqualTo("abc")
    response1.close()

    // Force a fresh connection for the next request.
    client.connectionPool.evictAll()

    // Confirm that a second request also succeeds. This should detect caching problems.
    server.enqueue(
      MockResponse
        .Builder()
        .body("def")

        writer.windowUpdate(0, (windowSize - DEFAULT_INITIAL_WINDOW_SIZE).toLong())
      }
    }
    // Thread doesn't use client Dispatcher, since it is scoped potentially across clients via
    // ConnectionPool.
    taskRunner.newQueue().execute(name = connectionName, block = readerRunnable)
  }

  /** Merges [settings] into this peer's settings and sends them to the remote peer. */
  @Throws(IOException::class)

    val call1 = client.newCall(Request(server.url("/")))
    val response = call1.execute()
    call1.cancel()

    // That connection is pooled, and it works.
    assertThat(client.connectionPool.connectionCount()).isEqualTo(1)
    val call2 = client.newCall(Request(server.url("/")))
    val response2 = call2.execute()
    assertThat(response2.body.string()).isEqualTo("def")