*/
internal class FailedPlan(
  e: Throwable,
) : RoutePlanner.Plan {
  val result = RoutePlanner.ConnectResult(plan = this, throwable = e)

  override val isReady = false

  override fun connectTcp() = result

  override fun connectTlsEtc() = result

  override fun handleSuccess() = error("unexpected call")

  override fun cancel() = error("unexpected cancel")

  /**
   * A plan holds either an immediately-usable connection, or one that must be connected first.
   * 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()

    /**

      check(connectTlsNextPlan == null)
      return FakePlan(nextPlanId++)
        .also {
          connectTlsNextPlan = it
        }
    }

    override fun connectTcp(): ConnectResult {
      check(connectState == ConnectState.READY)
      events += "plan $id TCP connecting..."

      taskFaker.sleep(tcpConnectDelayNanos)

      if (yieldBeforeTcpConnectReturns) {

      routes = routes,
      attempt = attempt,
      tunnelRequest = tunnelRequest,
      connectionSpecIndex = connectionSpecIndex,
      isTlsFallback = isTlsFallback,
    )

  override fun connectTcp(): ConnectResult {
    check(rawSocket == null) { "TCP already connected" }

    var success = false

    // Tell the call about the connecting call so async cancels work.
    user.addPlanToCancel(this)