[bitwalker]

async/await are just sugar over the much older asynchronous delegate pattern that has been in the language since day one. So yes, they were.

[dsego]

are they widely used in APIs to e.g. send a query to the sql database or open a file?

[jussij]

Yes.

In .Net 4.5 there are Async versions of the web, file, stream, image and SQL category of functions.

It's also making its way into ASP.Net layer.