[carlmr]

Not OP, but I think the problem they are trying to explain is that if you create an async function it can only be called from other async functions, so it's quite an infectious concept.

If you create a library that uses async, you're forcing everybody that uses the library into async as well (with the same executor).

If somebody writes a library now that's generally useful but uses async, it forces others to use async or rewrite the library themselves.

On the one hand a lot of people put this down as whining about free code, which is somewhat true, but the infectious nature makes the whole ecosystem less useful if you want to build something non-async.

[lcall]

I think this is not true. I found a way (in the async book or tokio documentation, somewhere near the end of the docs or end of a quick-start guide or such) to just call it and not have to make the calling function async, using runtime.block_on() .

If you request here or via the email at my web site (in profile), I can provide a more detailed example from a test I have.

(note to self: see fn test_basic_sql_connectivity_with_async_and_tokio() .)