In `QueryAsync<Dynamic>` you will get back an `IEnumerable<object>` requiring you to use `.Cast<IDictionary<String,Object>>()` to get the desired behavior.
However, `Query` returns an `IEnumerable<DapperRow>` so you can use a simple cast or as to  `IEnumerable<IDictionary<string,object>>`

I propose this change to allow this code to just work::
```csharp
var rows = await QueryAsync(cnn, sql) as IEnumerable<IDictionary<string,object>>;
```