I don't know how RetroArch is architected in regards to interacting with the cores, but if it does so by calling a `run_frame()` function or something similar,

I don't know how RetroArch is architected in regards to interacting with the cores, but if it does so by calling a `run_frame()` function or something similar, then all it has to do is delay calls to that function. I imagine it is a bit more complicated than that though.