I need send and receive reliable datagrams between peers (by using RPC). Every peer is service in service-oriented architecture. But any peer may be written on Python or C++ (Python services with asyncio and C++ Unreal Engine 4 instances - clients and servers).
So I search for done RUDP implementations for C++ and Python both.
What are RUDP implementations best to use for this task?
I do not think so. UDP is not reliable. TCP is, but UDP is faster. Here is a comparison between UDP and TCP on this link, I recommend reading it.
That said, this repo claims to have TCP reliability in UDP (C++): https://github.com/dileepramesh/Reliable-UDP
Also, please take a look at this link: Simple Reliable UDP C++ Libraries
it recommends boost::asio and ACE.