I'm coming from Java and there we use the EPoll selector implementation that comes with the JDK for non-blocking / asynchronous networking TCP and UDP development. Therefore you don't have to make choices.
But when it comes to C++ there are dozens of options to choose from according to this answer: https://stackoverflow.com/questions/118945/best-c-c-network-library
I don't have experience with C++ so I don't know. Which one should I pick for low-latency, asynchronous, non-blocking, real-time, selector style network programming? Does C++ even have a standard non-blocking network library or are they all external / independent?