_2019-06-26_

**This release upgrades OkHttp to Kotlin.** We tried our best to make fast and safe to upgrade
from OkHttp 3.x. We wrote an [upgrade guide][upgrading_to_okhttp_4] to help with the migration and a
[blog post][okhttp4_blog_post] to explain it.

 *  Fix: Target Java 8 bytecode for Java and Kotlin.


## Version 4.0.0-RC3

_2019-06-24_

    // our connection coalescing requirements are met. See also:
    // https://hpbn.co/optimizing-application-delivery/#eliminate-domain-sharding
    // https://daniel.haxx.se/blog/2016/08/18/http2-connection-coalescing/

    // 1. This connection must be HTTP/2.
    if (http2Connection == null) return false

    // 2. The routes must share an IP address.

          if (!buffer.isProbablyUtf8()) {
            logger.log("")
            logger.log("<-- END HTTP (${totalMs}ms, binary ${buffer.size}-byte body omitted)")
            return response
          }

          if (contentLength != 0L) {
            logger.log("")
            logger.log(buffer.clone().readString(charset))
          }

          logger.log(
            buildString {

    address: InetSocketAddress,
    connectTimeout: Int,
  ) {
    socket.connect(address, connectTimeout)
  }

  open fun log(
    message: String,
    level: Int = INFO,
    t: Throwable? = null,
  ) {
    val logLevel = if (level == WARN) Level.WARNING else Level.INFO
    logger.log(logLevel, message, t)
  }

  open fun isCleartextTrafficPermitted(hostname: String): Boolean = true

  /**

          responseCallback.onResponse(this@RealCall, response)
        } catch (e: IOException) {
          if (signalledCallback) {
            // Do not signal the callback twice!
            Platform.get().log("Callback failure for ${toLoggableString()}", Platform.INFO, e)
          } else {
            responseCallback.onFailure(this@RealCall, e)
          }
        } catch (t: Throwable) {
          cancel()

  }

  @Test fun specialKInHostname() {
    // https://github.com/apache/httpcomponents-client/commit/303e435d7949652ea77a6c50df1c548682476b6e
    // https://www.gosecure.net/blog/2020/10/27/weakness-in-java-tls-host-verification/
    val heldCertificate =
      HeldCertificate.Builder()
        .commonName("Foo Corp")
        .addSubjectAlternativeName("k.com")

    val response = client.newCall(request).execute()

    val results =
      response.use {
        moshi.adapter(HowsMySslResults::class.java).fromJson(response.body.string())!!
      }

    Platform.get().log("results $results", Platform.WARN)

    assertTrue(results.session_ticket_supported)
    assertEquals("Probably Okay", results.rating)
    // TODO map to expected versions automatically, test ignored for now.  Run manually.

        // or mostly silently with an IOException
        url = urlLine.toHttpUrlOrNull() ?: throw IOException("Cache corruption for $urlLine").also {
          Platform.get().log("cache corruption", WARN, it)
        }
        requestMethod = source.readUtf8LineStrict()
        val varyHeadersBuilder = Headers.Builder()
        val varyRequestHeaderLineCount = readInt(source)

      }

    fun assertNoMoreLogs() {
      assertThat(logs.size, "More messages remain: ${logs.subList(index, logs.size)}")
        .isEqualTo(index)
    }

    override fun log(message: String) {
      logs.add(message)
    }
  }

  companion object {
    private val PLAIN = "text/plain; charset=utf-8".toMediaType()
  }

        val cacheRequest = cache.put(response.newBuilder().request(cacheNetworkRequest).build())
        return cacheWritingResponse(cacheRequest, response).also {
          if (cacheResponse != null) {
            // This will log a conditional cache miss only.
            listener.cacheMiss(call)
          }
        }
      }

      if (HttpMethod.invalidatesCache(networkRequest.method)) {
        try {