QNetworkReply::attribute(HttpReasonPhraseAttribute) returns empty value when Http2 is used

#include <QCoreApplication>
#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QNetworkRequest>int count = 0;
void printResultAndQuit(QCoreApplication &app, QNetworkReply *reply)
{
    qDebug() << (reply->attribute(QNetworkRequest::Http2WasUsedAttribute).toBool() ? "HTTP2"
                                                                                   : "HTTP1")
             << reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt()
             << reply->attribute(QNetworkRequest::HttpReasonPhraseAttribute).toString();    ++count;
    if (count >= 2)
        app.quit();
}int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);    QNetworkAccessManager nam;    auto url = QUrl("https://qt.io");
    QNetworkRequest http1;
    http1.setUrl(url);
    http1.setAttribute(QNetworkRequest::Http2AllowedAttribute, false);
    QNetworkRequest http2;
    http2.setUrl(url);
    http2.setAttribute(QNetworkRequest::Http2AllowedAttribute, true);    auto *reply1 = nam.get(http1);
    auto *reply2 = nam.get(http2);    QObject::connect(reply1, &QNetworkReply::finished, [&]() { printResultAndQuit(a, reply1); });
    QObject::connect(reply2, &QNetworkReply::finished, [&]() { printResultAndQuit(a, reply2); });    return a.exec();
}