Creating PersonsCsvBinder
Let's build a binder.
To create ModelBinder, add a new class called PersonsCsvBinder, which implements IModelBinder. In the BindModelAsync method, we get ModelBindingContext with all the information in it that we need in order to get the data and to deserialize it. The following code snippets show a generic binder that should work with any list of models. We have split it into sections so that you can clearly see how each part of the binder works:
public class PersonsCsvBinder : IModelBinder
{
    public async Task BindModelAsync(
        ModelBindingContext bindingContext)
    {
        if (bindingContext == null)
        {
            return;
        }
      ...
