Async await how to use return values

Question

I have a windows service that I have inherited from another developer, it runs very slow and has numerous slow call to the eBay API. I wish to speed it up without too much refac

Answer 1

Use Result property on Task class:

await Task.WhenAll(partNumberCollection, additionalProductDetials);

var partNumberCollectionResult = partNumberCollection.Result;
var additionalProductDetialsResult = additionalProductDetials.Result;