You can spin up a single threaded runtime to perform these async calls without the need to "infect" the rest of the program.

The strategy is to spin up a single threaded async runtime and to just perform that call and block on the runtime itself. The easiest way to do that is probably https://github.com/zesterer/pollster

And there really isn't much in there so you didn't need to worry about performance or anything like that.

I recently refactored a colleague's program from async to sync because it's essentially and entirely sequential.

The reason it started its life as async was the reqwest library, which first and foremost provides async methods to perform http requests.

However, tucked away behind a feature flag aptly named `blocking` there is a small API that wraps the async api and allows making sync/blocking calls in a non-async main. And there they employ the same strategy of having a thin async runtime that blocks on completion of the async call.