set "flags" property on playbin object

Hi guys,

I am trying to set the flags propery on a playbin object as created in the gstplaystream.lua example, but I am not able to get to the flags property.
Flags:
https://developer.gnome.org/gst-plugins-libs/stable/gst-plugins-base-plugins-playbin.html#GstPlayBin--flags

I've compared it to the python gi interface and I get the same problems:
http://gstreamer-devel.966125.n4.nabble.com/How-to-reach-GstPlayFlags-for-PlayBin-through-GObject-introspection-td4657571.html
If I would print(play.flags), I get 32. If I try to play.flags=0x253 I get a RO object.
So just as with the python gi, there is probably another flags, but it isn't the playbins property.
But unlike the python gi, I cannot find a comparable ow f*ck
Gst.util_set_object_arg(play,"flags",0x253)
is exactly what I need, and the python syntax just works on lua-lgi.
So I am making this an issue for documentation, because:
play.uri="http://..." works fine, but:
play.flags=0x253 does not work as it does not access the flags property of the play structure, but another thing called flags, and I am not involved enough to know what.
I also don't think that an override should be placed, but just a hint in the documentation.
If I played around with it long enough I might make a documentation patch.

Start with the gstplaystream.lua example and the linked GStreamer playbin flags documentation, then compare how lua-lgi exposes play.uri and play.flags. Clarify the documented way to access or set GstPlayFlags through this binding, including why direct assignment does not work; the documentation should let users configure flags without guessing.