Although the setting of max-frame-size is currently not possible with the python reactive API (ENTMQCL-454), there is _set_max_frame_size(size) method available on the Transport object. I tried to play with the values a bit using following code:

  def on_session_init(self, event):
     event.transport._set_max_frame_size(VALUE)

I noticed that the receiver is not able to receive messages when the value for max-frame-size is larger than 2^20 (1048576) bytes (remote_max_frame_size is 4294967295). I'm not really sure if that is expected. This may be reproduced when adding the code above ie.: to simple_recv.py.

Note: This is not a good use case as setting the max-frame-size in on_session_init is really too late. But given that it is too late to set the max-frame-size, I would expect it won't have any effect on the client. So, I'm raising the issue mainly to not forget retesting this behaviour when the ENTMQCL-454 gets implemented.