pool: RealConnectionPool,
    route: Route,
    idleAtNanos: Long = Long.MAX_VALUE,
    taskRunner: TaskRunner = this.taskRunner,
  ): RealConnection {
    val result =
      RealConnection.newTestConnection(
        taskRunner = taskRunner,
        connectionPool = pool,
        route = route,
        socket = Socket(),
        idleAtNs = idleAtNanos,
      )
    result.withLock { pool.put(result) }

      " cipherSuite=${handshake?.cipherSuite ?: "none"}" +
      " protocol=$protocol}"
  }

  companion object {
    const val IDLE_CONNECTION_HEALTHY_NS = 10_000_000_000 // 10 seconds.

    fun newTestConnection(
      taskRunner: TaskRunner,
      connectionPool: RealConnectionPool,
      route: Route,
      socket: Socket,
      idleAtNs: Long,
    ): RealConnection {
      val result =