*  New: Build with Kotlin 1.3.41, BouncyCastle 1.62, and Conscrypt 2.2.1.
 *  Fix: Recover gracefully when a coalesced connection immediately goes unhealthy.
 *  Fix: Defer the `SecurityException` when looking up the default proxy selector.
 *  Fix: Don't use brackets formatting IPv6 host names in MockWebServer.
 *  Fix: Don't permit cache iterators to remove entries that are being written.


## Version 4.0.1

_2019-07-10_

![Events Diagram](../assets/images/******@****.***)

### Events with Retries and Follow-Ups

OkHttp is resilient and can automatically recover from some connectivity failures. In this case, the `connectFailed()` event is not terminal and not followed by `callFailed()`. Event listeners will receive multiple events of the same type when retries are attempted.

 *
 * Supported on OpenJDK 9+ via SSLParameters and SSLSocket features.
 *
 * ### Trust Manager Extraction
 *
 * Supported on Android 2.3+ and OpenJDK 7+. There are no public APIs to recover the trust
 * manager that was used to create an [SSLSocketFactory].
 *
 * Not supported by choice on JDK9+ due to access checks.
 *
 * ### Android Cleartext Permit Detection
 *

    `HttpUrl.Builder.addEncodedQueryParameter()`.
 *  New: CBC-mode ECDSA cipher suites have been removed from OkHttp's default
    configuration: `TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA` and
    `TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA`. This tracks a [Chromium
    change][remove_cbc_ecdsa] to remove these cipher suites because they are
    fragile and rarely-used.

      val randomAccessFile = RandomAccessFile(file, "rw")
      val result = Relay(randomAccessFile, upstream, 0L, metadata, bufferMaxSize)

      // Write a dirty header. That way if we crash we won't attempt to recover this.
      randomAccessFile.setLength(0L)
      result.writeHeader(PREFIX_DIRTY, -1L, -1L)

      return result
    }

    /**
     * Creates a relay that reads a recorded stream from [file].
     *

fun retryTlsHandshake(e: IOException): Boolean {
  return when {
    // If there was a protocol problem, don't recover.
    e is ProtocolException -> false

    // If there was an interruption or timeout (SocketTimeoutException), don't recover.
    // For the socket connect timeout case we do not try the same host with a different
    // ConnectionSpec: we assume it is unreachable.

      }
    }
  }

  /**
   * Report and attempt to recover from a failure to communicate with a server. Returns true if
   * `e` is recoverable, or false if the failure is permanent. Requests with a body can only
   * be recovered if the body is buffered or if the failure occurred before the request has been
   * sent.
   */
  private fun recover(
    e: IOException,
    call: RealCall,
    userRequest: Request,

   caused an IOException.
 * Fix bug in HTTP/2 where our HPACK decoder wasn't emitting entries in
   certain eviction scenarios, leading to dropped response headers.

## Version 1.5.1

_2014-03-11_

 * Fix 1.5.0 regression where connections should not have been recycled.
 * Fix 1.5.0 regression where transparent Gzip was broken by attempting to
   recover from another I/O failure.

 5. It sends the HTTP request and reads the response.

If there's a problem with the connection, OkHttp will select another route and try again. This allows OkHttp to recover when a subset of a server's addresses are unreachable. It's also useful when a pooled connection is stale or if the attempted TLS version is unsupported.

 * Transparent GZIP shrinks download sizes.
 * Response caching avoids the network completely for repeat requests.

OkHttp perseveres when the network is troublesome: it will silently recover from common connection
problems. If your service has multiple IP addresses, OkHttp will attempt alternate addresses if the
first connect fails. This is necessary for IPv4+IPv6 and services hosted in redundant data