// Close the raw socket so we don't end up doing synchronous I/O.
    rawSocket?.closeQuietly()
  }

  override fun socket(): Socket = socket!!

  /** Returns true if this connection is ready to host new streams. */
  fun isHealthy(doExtensiveChecks: Boolean): Boolean {
    lock.assertNotHeld()

    val nowNs = System.nanoTime()

    val rawSocket = this.rawSocket!!
    val socket = this.socket!!

 *  Fix: Don't call `EventListener.responseHeadersStart()` or `responseBodyStart()` until bytes have
    been received. Previously these events were incorrectly sent too early, when OkHttp was ready to
    read the response headers or body, which mislead tracing tools. Note that the `responseFailed()`
    event always used to follow one of these events; now it may be sent without them.

 *  New: Upgrade to Kotlin 1.3.61.

   * [Call.request] is a redirect to a different address.
   *
   * Prior to OkHttp 4.3 this was incorrectly invoked when the client was ready to read headers.
   * This was misleading for tracing because it was too early.
   */
  open fun responseHeadersStart(call: Call) {
  }

  /**
   * Invoked immediately after receiving response headers.
   *

        if (connections.isEmpty()) cleanupQueue.cancelAll()

        // Clean up again immediately.
        return 0L
      }

      earliestEvictableConnection != null -> {
        // A connection will be ready to evict soon.
        return earliestEvictableIdleAtNs + keepAliveDurationNs - now
      }

      inUseConnectionCount > 0 -> {

              if (errorExceptionToDeliver == null &&
                unacknowledgedBytesRead >= connection.okHttpSettings.initialWindowSize / 2
              ) {
                // Flow control: notify the peer that we're ready for more data! Only send a
                // WINDOW_UPDATE if the stream isn't in error.
                connection.writeWindowUpdateLater(id, unacknowledgedBytesRead)

    assertThat(redirect.requestLine).isEqualTo("GET /new-path HTTP/1.1")
  }

  /**
   * Test that MockWebServer blocks for a call to enqueue() if a request is made before a mock
   * response is ready.
   */
  @Test
  fun dispatchBlocksWaitingForEnqueue() {
    Thread {
      try {
        Thread.sleep(1000)
      } catch (ignored: InterruptedException) {
      }
      server.enqueue(

    ```

### Asynchronous Get ([.kt][AsynchronousGetKotlin], [.java][AsynchronousGetJava])

Download a file on a worker thread, and get called back when the response is readable. The callback is made after the response headers are ready. Reading the response body may still block. OkHttp doesn't currently offer asynchronous APIs to receive a response body in parts.

=== ":material-language-kotlin: Kotlin"
    ```kotlin
      private val client = OkHttpClient()

    try {
      while (tcpConnectsInFlight.isNotEmpty() || routePlanner.hasNext()) {
        if (routePlanner.isCanceled()) throw IOException("Canceled")

        // Launch a new connection if we're ready to.
        val now = taskRunner.backend.nanoTime()
        var awaitTimeoutNanos = nextTcpConnectAtNanos - now
        var connectResult: ConnectResult? = null

        responseBodyComplete()
      }
      closed = true
    }
  }

  companion object {
    private const val NO_CHUNK_YET = -1L

    private const val STATE_IDLE = 0 // Idle connections are ready to write request headers.
    private const val STATE_OPEN_REQUEST_BODY = 1
    private const val STATE_WRITING_REQUEST_BODY = 2
    private const val STATE_READ_RESPONSE_HEADERS = 3

  private var protocol: Protocol? = null
  private var source: BufferedSource? = null
  private var sink: BufferedSink? = null
  private var connection: RealConnection? = null

  /** True if this connection is ready for use, including TCP, tunnels, and TLS. */
  override val isReady: Boolean
    get() = protocol != null

  private fun copy(
    attempt: Int = this.attempt,
    tunnelRequest: Request? = this.tunnelRequest,