Linq methods for IAsyncEnumerable

Question

When working with an IEnumerable there are the build-in extension methods from the System.Linq namespace such as Skip,

Answer 1

There is, in the System.Linq.Async namespace from the System.Reactive package. If you don't want the full System.Reactive package, you can use the System.Linq.Async package directly (it's part of System.Reactive).
You can read this github issue. The source for System.Linq.Async can be found here.