QNetworkAccessManager can't decompress response data that received from HTTP server automatically

const QString KAcceptEncoding( "gzip" );
aNetworkRequest.setRawHeader("Accept-Encoding", KAcceptEncoding.toAscii());

then response was processed as below:

void onFinished(QNetworkReply *aNwkReply)
{
    if(aNwkReply->error() != QNetworkReply::NoError)
    {
        LOG_FORMAT("Error received: %s", STRING2CHAR(aNwkReply->errorString()));
        emit errorNotified(true);
        return;
    }
    
    mNwkReply = aNwkReply;
    
    QByteArray response1 = mNwkReply->readAll();

    mNwkReply->deleteLater();
    mNwkReply = NULL;
    
    //here the data read into variable response1 is still in compressed format.
}