A HtmlFormatter to allow conneg of HTML in MVC6

gistfile1.cs

public class HtmlFormatter : OutputFormatter
    {
        public HtmlFormatter()
        {
            SupportedEncodings.Add(Encodings.UTF8EncodingWithoutBOM); // Whatever this should be
            SupportedEncodings.Add(Encodings.UTF16EncodingLittleEndian); // Whatever this should be
            SupportedMediaTypes.Add(MediaTypeHeaderValue.Parse("text/html"));
        }

        public override bool CanWriteResult(OutputFormatterContext context, MediaTypeHeaderValue contentType)
        {
            return true;
        }

        public override async Task WriteResponseBodyAsync(OutputFormatterContext context)
        {
            
            if (context.Object == null)
            {
                // if the value is null don't write anything.
                return;
            }
                                                // Obviously this doesn't compile, but you get the idea
            var viewData = new ViewDataDictionary<context.DeclaredType>(new DataAnnotationsModelMetadataProvider());
            viewData.Model = context.Object;
            
            var viewResult = new ViewResult();
            
            viewResult.ViewData = viewData;
            await viewResult.ExecuteResultAsync(context.ActionContext);
        }
    }