据我所知，cURL是PHP中唯一支持HTTP的传输方法2.0。

As far as I'm aware, cURL is the only transfer method in PHP that supports HTTP 2.0.

您首先需要测试您的cURL版本是否可以支持它，然后设置正确的版本标头：

You'll first need to test that your version of cURL can support it, and then set the correct version header:

if (curl_version()["features"] & CURL_VERSION_HTTP2 !== 0) {
    $url = "https://www.google.com/";
    $ch = curl_init();
    curl_setopt_array($ch, [
        CURLOPT_URL            =>$url,
        CURLOPT_HEADER         =>true,
        CURLOPT_NOBODY         =>true,
        CURLOPT_RETURNTRANSFER =>true,
        CURLOPT_HTTP_VERSION   =>CURL_HTTP_VERSION_2_0,
    ]);
    $response = curl_exec($ch);
    if ($response !== false && strpos($response, "HTTP/2") === 0) {
        echo "HTTP/2 support!";
    } elseif ($response !== false) {
        echo "No HTTP/2 support on server.";
    } else {
        echo curl_error($ch);
    }
    curl_close($ch);
} else {
    echo "No HTTP/2 support on client.";
}