If you use Result means that your method will block. But it isn't recommended because it will cause a deadlock. You need to be careful when you use Result property or Wait().
When you use async method I recommend you que you declare async method and you call the function with await.
public async Task Method()
{
HttpResponseMessage myResponse = await myClient.PostAsync(theUri, theContent);
}
If you can't declare the method as async and you need to use a async method. I recommend you that use this class for convert async method in sync method:
How would I run an async Task<T> method synchronously?