could use new flow control capacity before acknowledging it, causing strict HTTP/2 servers to
    fail the call.


## Version 4.1.1

_2019-09-05_

 *  Fix: Don't drop repeated headers when validating cached responses. In our Kotlin upgrade we
    introduced a regression where we iterated the number of unique header names rather than then

    lock.assertHeld()

    // If this connection is not accepting new exchanges, we're done.
    if (calls.size >= allocationLimit || noNewExchanges) return false

    // If the non-host fields of the address don't overlap, we're done.
    if (!this.route.address.equalsNonHost(address)) return false

    // If the host exactly matches, we're done: this connection can carry the address.

        if (toClose != null) {
          connection.connectionListener.connectionClosed(connection)
        }
      } else {
        check(toClose == null) // If we still have a connection we shouldn't be closing any sockets.
      }
    }

    val result = timeoutExit(e)
    if (e != null) {
      eventListener.callFailed(this, result!!)
    } else {

  private var coordinatorWakeUpAt = 0L

  /**
   * When we need a new thread to run tasks, we call [Backend.execute]. A few microseconds later we
   * expect a newly-started thread to call [Runnable.run]. We shouldn't request new threads until
   * the already-requested ones are in service, otherwise we might create more threads than we need.
   *
   * We use [executeCallCount] and [runCallCount] to defend against starting more threads than we

    try {
      networkResponse = chain.proceed(networkRequest)
    } finally {
      // If we're crashing on I/O or otherwise, don't leak the cache body.
      if (networkResponse == null && cacheCandidate != null) {
        cacheCandidate.body.closeQuietly()
      }
    }

    // If we have a cache response too, then we're doing a conditional get.
    if (cacheResponse != null) {

          return tunnelResult
        }
      }

      if (route.address.sslSocketFactory != null) {
        // Assume the server won't send a TLS ServerHello until we send a TLS ClientHello. If
        // that happens, then we will have buffered bytes that are needed by the SSLSocket!
        // This check is imperfect: it doesn't tell us whether a handshake will succeed, just

    )
    assertThat(webSocket.close(1000, null)).isFalse()
  }

  /**
   * There's no read timeout when reading the first byte of a new frame. But as soon as we start
   * reading a frame we enable the read timeout. In this test we have the server returning the first
   * byte of a frame but no more frames.
   */
  @Test
  fun readTimeoutAppliesWithinFrames() {
    webServer.dispatcher =

 *  Breaking: Drop support for Kotlin Multiplatform.

    We planned to support multiplatform in OkHttp 5.0, but after building it, we weren't happy with
    the implementation trade-offs. We can't use our HTTP client engine on Kotlin/JS, and we weren't
    prepared to build a TLS API for Kotlin/Native.

    We'd prefer a multiplatform HTTP client API that's backed by OkHttp on Android and JVM, and

      if (retryRoute != null) {
        // Lock in the route because retryRoute() is racy and we don't want to call it twice.
        nextRouteToTry = retryRoute
        return true
      }
    }

    // If we have a routes left, use 'em.
    if (routeSelection?.hasNext() == true) return true

    // If we haven't initialized the route selector yet, assume it'll have at least one route.

  }

  /**
   * Don't call through to the proxy selector if we don't have a host name.
   * https://github.com/square/okhttp/issues/5770
   */
  @Test fun proxySelectorNotCalledForNullHost() {
    // The string '>' is okay in a hostname in HttpUrl, which does very light hostname validation.
    // It is not okay in URI, and so it's stripped and we get a URI with a null host.
    val bogusHostname = ">"
    val address =