Many thanks for the long write of tips and experience :)
Some of the points, I have given a little thought and some of them I didn’t even think about until now. Especially the point about overworked channel hubs is a thing I should pay more attention to.
In my application, I can easily split most of my subscribers into channels based on which group of IoT devices it is interested in.
I might be able to use Flub directly as a replacement of my early stage
Hub, which was put into production today :)
I will have a closer look at Hub, Flub and your very nice list of advices tomorrow.