Has anything like RR been developed for the .net Core CLR or Framework?
I've only used it with C++ applications so far, but the WinDbg blog claims that it also works when debugging managed code with the SOS debugging extension.
Visual Studio confusingly has the somewhat-similar "Intellitrace", but AFAIK that only records previous states collected for certain events (breakpoints, first-chance-exceptions, ...). It can't rewind the program an arbitrary point like the time-travel debugger can, so it's not useful to follow data flow.