System.out.println("REQUEST 1 (new connection)");
try (Response response = client.newCall(request).execute()) {
  // Consume and discard the response body.
  response.body().source().readByteString();
}

System.out.println("REQUEST 2 (pooled connection)");
try (Response response = client.newCall(request).execute()) {
  // Consume and discard the response body.
  response.body().source().readByteString();
}
```

## Version 4.4.1

_2020-03-08_

 *  Fix: Don't reuse a connection on redirect if certs match but DNS does not. For better
    locality and performance OkHttp attempts to use the same pooled connection across redirects and
    follow-ups. It independently shares connections when the IP addresses and certificates match,
    even if the host names do not. In 4.4.0 we introduced a regression where we shared a connection

      expected.assertSuppressed { throwables: List<Throwable>? ->
        assertThat(throwables!!.size).isEqualTo(1)
      }
    }
  }

  /**
   * When a pooled connection fails, don't blame the route. Otherwise pooled connection failures can
   * cause unnecessary SSL fallbacks.
   *
   * https://github.com/square/okhttp/issues/515
   */
  @Test
  fun sslFallbackNotUsedWhenRecycledConnectionFails() {

        when {
          client.fastFallback -> FastFallbackExchangeFinder(routePlanner, client.taskRunner)
          else -> SequentialExchangeFinder(routePlanner)
        }
    }
  }

  /** Finds a new or pooled connection to carry a forthcoming request and response. */
  internal fun initExchange(chain: RealInterceptorChain): Exchange {
    this.withLock {
      check(expectMoreExchanges) { "released" }

 * follow-up requests. The client is unblocked and free to continue as soon as it has received the
 * entire response body. If and when the client makes a subsequent request using a pooled socket the
 * server may not have had time to close the socket. The socket will be closed at an indeterminate
 * point before or during the second request. It may be closed after client has started sending the

 * **Exchange** carries a single HTTP request/response pair.

 * **ExchangeFinder** chooses which connection carries each exchange. Where possible it will use the same connection for all exchanges in a single call. It prefers reusing pooled connections over establishing new connections.      

#### Per-Connection Locks

  }

  /**
   * Sets the delegate of `timeout` to [Timeout.NONE] and resets its underlying timeout
   * to the default configuration. Use this to avoid unexpected sharing of timeouts between pooled
   * connections.
   */
  private fun detachTimeout(timeout: ForwardingTimeout) {
    val oldDelegate = timeout.delegate
    timeout.setDelegate(Timeout.NONE)
    oldDelegate.clearDeadline()

    assertThat(server.takeRequest().sequenceNumber).isEqualTo(2)
  }

  /**
   * Each OkHttpClient used to get its own instance of NullProxySelector, and because these weren't
   * equal their connections weren't pooled. That's a nasty performance bug!
   *
   * https://github.com/square/okhttp/issues/5519
   */
  @Test
  fun connectionPoolingWithFreshClientSamePool() {
    server.enqueue(MockResponse(body = "abc"))

 * Fix: Support the `PATCH` method.
 * Fix: Support request bodies on `DELETE` method.
 * Fix: Drop the `okhttp-protocols` module.
 * Internal: Replaced internal byte array buffers with pooled buffers ("OkBuffer").


## Version 1.3.0

_2014-01-11_

 * New: Support for "PATCH" HTTP method in client and MockWebServer.
 * Fix: Drop `Content-Length` header when redirected from POST to GET.

## Retrying Requests

Sometimes connections fail: either a pooled connection was stale and disconnected, or the webserver itself couldn’t be reached. OkHttp will retry the request with a different route if one is available.

## [Calls](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-call/)