RxCpp VS mosquitto_transport

And, prior to that https://github.com/ReactiveX/RxCpp

Yeah, I know this problem with operators =), original RxCpp implementation also has this problem with implementing all functions into base class and calling dependent functions internally.

Also you can check rxcpp with documentation about reactive approach there. It is functional version of observer/publisher-subscriber patterns with ability to be multithreaded. You can send events from one side, subscribe from another and modify events in meanwhile

I use a very large header-only library RxCpp. Simply adding #include "RxCpp/rx.hpp" to one .cpp file adds >1 second of compilation time. I'd like to use it as a module, but when I try to import "RxCpp/rx.hpp";, I get a bunch of errors.

+1 for Rx, specifically RxCpp. I've used it in concert with Qt with great results.

mosquitto_transport, an experiment of writing SObjectizer-based wrapper around mosquitto library;

PS. Five years ago we used MQTT+SObjectizer in one of our projects, a part of it is available as [mosquitto_transport](https://github.com/Stiffstream/mosquitto_transport). You can take a look at it and get an idea of how MQTT and SObjectizer can be integrated together (maybe it's not a best way, but that approach worked well for us).