val index = serialTaskQueue.indexOfFirst { it.isReady() }
    if (index == -1) return null

    val nextTask = serialTaskQueue.removeAt(index)
    currentTask = nextTask
    contextSwitchCount++
    nextTask.start()
    return nextTask
  }

  private interface SerialTask {
    /** Returns true if this task is ready to start. */
    fun isReady() = true

        idleAtNanos = defaultConnectionIdleAtNanos,
      )
    var retry: FakePlan? = null
    var retryTaken = false
    var yieldBeforePlanReturns = false

    override val isReady: Boolean
      get() = connectState == ConnectState.TLS_CONNECTED

    var tcpConnectDelayNanos = 0L
    var tcpConnectThrowable: Throwable? = null
    var yieldBeforeTcpConnectReturns = false

  private lateinit var socket: BufferedSocket
  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,
    connectionSpecIndex: Int = this.connectionSpecIndex,

   * These steps are split so callers can call [connectTcp] on a background thread if attempting
   * multiple plans concurrently.
   */
  interface Plan {
    val isReady: Boolean

    fun connectTcp(): ConnectResult

    fun connectTlsEtc(): ConnectResult

    fun handleSuccess(): RealConnection

    fun cancel()

    /**

                while (true) {
                    final int read = fis.read(b[i]);
                    synchronized (w) {
                        w.checkException();
                        while (!w.isReady()) {
                            try {
                                w.wait();
                            } catch (final InterruptedException ie) {

            @Override
            public void write(int b) throws IOException {
                outputStream.write(b);
            }

            @Override
            public boolean isReady() {
                return true;
            }

            @Override
            public void setWriteListener(WriteListener listener) {
            }
        };

        synchronized (w) {
            long deadline = System.currentTimeMillis() + 2000;
            while (!w.isReady() && System.currentTimeMillis() < deadline) {
                w.wait(10);
            }
            assertTrue(w.isReady(), "WriterThread should be ready to accept work");

            // Act: submit a write
            w.write(payload, 3, out);
        }

          cancelInFlightConnects()

          // Finish connecting. We won't have to if the winner is from the connection pool.
          if (!connectResult.plan.isReady) {
            connectResult = connectResult.plan.connectTlsEtc()
          }

          if (connectResult.isSuccess) {
            return connectResult.plan.handleSuccess()
          }
        }

        doExtensiveHealthChecks = doExtensiveHealthChecks,
        address = address,
        call = call,
        routes = routes,
        requireMultiplexed = planToReplace != null && planToReplace.isReady,
      ) ?: return null

    // If we coalesced our connection, remember the replaced connection's route. That way if the
    // coalesced connection later fails we don't waste a valid route.

 *
 * <p>To use this class the concrete subclass must implement the {@link
 * IteratorTester#newTargetIterator()} method. This is because it's impossible to test an Iterator
 * without changing its state, so the tester needs a steady supply of fresh Iterators.
 *
 * <p>If your iterator supports modification through {@code remove()}, you may wish to override the
 * verify() method, which is called after each sequence and is guaranteed to be called