Disable nagle's algorithm (TCP_NODELAY) using QWebSocket

[Nowis]

I am using a QWebSocket in a client application and I need to disable nagle's algorithm used in TCP.

Fortunately, QWebSocket seems to disable it by default : QWebSocketImplementation, LowDelayOption

However, it does seems to have any effects on the TCP_NODELAY option. Using knetstat to view the socket option I get this :

SO_REUSEADDR=0,SO_REUSEPORT=0,SO_KEEPALIVE=0,TCP_NODELAY=0,TCP_DEFER_ACCEPT=0

So it looks like the option is not actually set. Am I missing something ?