RxCpp VS Disruptor-cpp

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.

If low latency / performance is important then something like aeron: https://github.com/real-logic/aeron or the disruptor pattern: https://github.com/Abc-Arbitrage/Disruptor-cpp are good options. Aeron supports network message but requires a driver to be running on the system even for IPC. Disruptor is thread to thread messaging only and doesn't need drivers etc - just a normal library.