The general guidance here is to try without it, trace performance, and if there's a specific issue that inlining can resolve, use inlining as needed. If your extension is defined in the same module that you're using it, it probably doesn't matter. It may matter in other circumstances, depending on how it's used and how your project is set up.
This particular init is basically a no-op in disguise, so inlining it won't have most of the downsides that inlining can have, so the risk of being overzealous is pretty small in this case. That's not always true.