* Don't start a new attempt until 250 ms after the most recent attempt was started.
 * Keep whichever TCP connection succeeds first and cancel all the others.
 * Race TCP only. Only attempt a TLS handshake on the winning TCP connection.

      check(connectState == ConnectState.READY)
      events += "plan $id TCP connecting..."

      taskFaker.sleep(tcpConnectDelayNanos)

      if (yieldBeforeTcpConnectReturns) {
        taskFaker.yield()
      }

      return when {
        tcpConnectThrowable != null -> {
          events += "plan $id TCP connect failed"

        if (connectResult == null) {
          connectResult = awaitTcpConnect(awaitTimeoutNanos, TimeUnit.NANOSECONDS) ?: continue
        }

        if (connectResult.isSuccess) {
          // We have a connected TCP connection. Cancel and defer the racing connects that all lost.
          cancelInFlightConnects()

          // Finish connecting. We won't have to if the winner is from the connection pool.

    assertThat(get("h3")).isEqualTo(Protocol.HTTP_3)
    assertThat(get("h3-29")).isEqualTo(Protocol.HTTP_3)
  }

  @Test
  fun testGetUnknown() {
    assertThrows(IOException::class.java) { get("tcp") }
  }

  @Test
  fun testToString() {
    assertThat(Protocol.HTTP_1_0.toString()).isEqualTo("http/1.0")
    assertThat(Protocol.HTTP_1_1.toString()).isEqualTo("http/1.1")

Similarly, the reader thread must never block on writing because this can deadlock the connection. Consider a client and server that both violate this rule. If you get unlucky, they could fill up their TCP buffers (so that writes block) and then use their reader threads to write a frame. Nobody is reading on either end, and the buffers are never drained.

#### Do-stuff-later pool

 *     lookups) and attempt a new connection them. When failures occur, retries iterate the list of
 *     available routes.
 *
 * If the pool gains an eligible connection while DNS, TCP, or TLS work is in flight, this finder
 * will prefer pooled connections. Only pooled HTTP/2 connections are used for such de-duplication.
 *
 * It is possible to cancel the finding process by canceling its call.
 *