* 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"

After this, the client and the server have an **encrypted TCP connection**, this is what TLS provides. And then they can use that connection to start the actual **HTTP communication**.

And that's what **HTTPS** is, it's just plain **HTTP** inside a **secure TLS connection** instead of a pure (unencrypted) TCP connection.

/// tip

接著，用戶端與 TLS 終止代理會以該憑證為基礎，**協商後續如何加密**整段 **TCP 通訊**。至此完成 **TLS 握手**。

之後，用戶端與伺服器之間就有一條**已加密的 TCP 連線**，這就是 TLS 所提供的能力。接著他們可以在這條連線上開始實際的 **HTTP** 通訊。

這也就是 **HTTPS** 的本質：在**安全的 TLS 連線**內傳送一般的 **HTTP**，而非在純（未加密）的 TCP 連線上。

/// tip

請注意，加密發生在 **TCP 層**，不是在 HTTP 層。

///

### HTTPS 請求 { #https-request }

現在用戶端與伺服器（更精確地說，是瀏覽器與 TLS 終止代理）之間已有**加密的 TCP 連線**，他們可以開始進行 **HTTP** 通訊。

import okhttp3.internal.platform.Platform
import okhttp3.internal.tls.OkHostnameVerifier
import okhttp3.internal.toHostHeader

/**
 * 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.

次に証明書を使用して、クライアントとTLS Termination Proxy は、 **TCP通信**の残りを**どのように暗号化するかを決定**します。これで**TLSハンドシェイク**の部分が完了します。

この後、クライアントとサーバーは**暗号化されたTCP接続**を持ちます。そして、その接続を使って実際の**HTTP通信**を開始することができます。

これが**HTTPS**であり、純粋な（暗号化されていない）TCP接続ではなく、**セキュアなTLS接続**の中に**HTTP**があるだけです。

/// tip | 豆知識

通信の暗号化は、HTTPレベルではなく、**TCPレベル**で行われることに注意してください。

///

### HTTPS リクエスト { #https-request }

      with:
        path: ~/go/pkg/mod
        key: ${{ runner.os }}-go-${{ matrix.go }}-${{ hashFiles('tests/go.mod') }}

    - name: Tests
      run: GITHUB_ACTION=true GORM_DIALECT=mysql GORM_DSN="gorm:gorm@tcp(localhost:9910)/gorm?charset=utf8&parseTime=True" ./tests/tests_all.sh

  mariadb:
    strategy:
      matrix:
        dbversion: [ 'mariadb:latest' ]
        go: ['stable', 'oldstable']

        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.

     * Used when authSchemeType is NTLM to configure the JCIFS engine.
     *
     * <p>Supported parameters include:</p>
     * <ul>
     * <li>jcifs.smb.client.SO_SNDBUF - TCP send buffer size</li>
     * <li>jcifs.smb.client.SO_RCVBUF - TCP receive buffer size</li>
     * <li>jcifs.smb.client.domain - Default domain</li>
     * <li>And other jcifs.* properties</li>
     * </ul>
     */

     * otherwise values must be between 1 and [Integer.MAX_VALUE] when converted to milliseconds.
     *
     * The connect timeout is applied when connecting a TCP socket to the target host. The default
     * value is 10 seconds.
     */
    fun connectTimeout(
      timeout: Long,
      unit: TimeUnit,
    ) = apply {