plan1.tcpConnectDelayNanos = 10.ms // Connect at time = 260 ms.
    plan1.tlsConnectDelayNanos = 10.ms // Connect at time = 270 ms.
    plan1.tlsConnectThrowable = IOException("boom!")

    val plan2 = plan1.createConnectTlsNextPlan()
    plan2.tcpConnectDelayNanos = 270.ms // Connect at time = 540 ms.

    val plan3 = plan0.createRetry()
    plan3.tcpConnectDelayNanos = 10.ms // Connect at time = 530 ms.

  ): Http2Connection {
    peer.setClient(client)
    peer.sendFrame().settings(settings!!)
    peer.acceptFrame() // ACK
    peer.play()
    return connect(peer)
  }

  /** Builds a new connection to `peer` with settings acked.  */
  private fun connect(
    peer: MockHttp2Peer,
    pushObserver: PushObserver = IGNORE,
    listener: Http2Connection.Listener = Http2Connection.Listener.REFUSE_INCOMING_STREAMS,

import okio.BufferedSource
import okio.buffer
import okio.sink
import okio.source

/**
 * A single attempt to connect to a remote server, including these steps:
 *
 *  * [TCP handshake][connectSocket]
 *  * Optional [CONNECT tunnels][connectTunnel]. When using an HTTP proxy to reach an HTTPS server
 *    we must send a `CONNECT` request, and handle authorization challenges from the proxy.
 *  * Optional [TLS handshake][connectTls].
 *

      }

      return when {
        tcpConnectThrowable != null -> {
          events += "plan $id TCP connect failed"
          ConnectResult(this, nextPlan = connectTcpNextPlan, throwable = tcpConnectThrowable)
        }
        canceled -> {
          events += "plan $id TCP connect canceled"
          ConnectResult(this, nextPlan = connectTcpNextPlan, throwable = IOException("canceled"))
        }

    val connect = planConnect()

    // Now that we have a set of IP addresses, make another attempt at getting a connection from
    // the pool. We have a better chance of matching thanks to connection coalescing.
    val pooled2 = planReusePooledConnection(connect, connect.routes)
    if (pooled2 != null) return pooled2

    return connect
  }

  /**

      "encrypted response from the origin server",
    )
    val connect = server.takeRequest()
    assertThat(connect.headers["Private"]).isNull()
    assertThat(connect.headers["User-Agent"]).isEqualTo(USER_AGENT)
    assertThat(connect.headers["Proxy-Connection"]).isEqualTo("Keep-Alive")
    assertThat(connect.headers["Host"]).isEqualTo("android.com:443")
    val get = server.takeRequest()

)

// LookupUserDN searches for the full DN and groups of a given short/login
// username.
func (l *Config) LookupUserDN(username string) (string, []string, error) {
	conn, err := l.LDAP.Connect()
	if err != nil {
		return "", nil, err
	}
	defer conn.Close()

	// Bind to the lookup user account
	if err = l.LDAP.LookupBind(conn); err != nil {
		return "", nil, err
	}

	// Lookup user DN

	ztunnelKeepAliveCheckInterval = time.Second / 10
	mt := monitortest.New(t)
	setupLogging()
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	fixture := connect(ctx)
	ztunClient := fixture.ztunClient
	uid := fixture.uid

	m, fds := readRequest(t, ztunClient)
	// we got am essage from ztun, so it should have observed us being connected

So, you will be able to see it all in the interactive API docs.

## Connect and disconnect

* Create your `FastAPI` application.
* Create event handlers to connect and disconnect from the database.

```Python hl_lines="42  45-47  50-52"
{!../../../docs_src/async_sql_databases/tutorial001.py!}
```

## Read notes

import okhttp3.Route

/**
 * A denylist of failed routes to avoid when creating a new connection to a target address. This is
 * used so that OkHttp can learn from its mistakes: if there was a failure attempting to connect to
 * a specific IP address or proxy server, that failure is remembered and alternate routes are
 * preferred.
 */
class RouteDatabase {
  private val _failedRoutes = mutableSetOf<Route>()