How do you do a IHttpHandler in v8?

I used IHttpHandler in v7 and it works ok, this is my v8.1.3 code, it doesn't get hit on a debug break.

namespace mysite
{
    public class CustomHttpHandler : UmbracoHttpHandler
    {
        //public CustomHttpHandler() { }
        public void Dispose() { }
        //public override bool IsReusable => false;
        public override bool IsReusable //IHttpHandler.IsReusable
        {
            get { return false; }
        }

        // void IHttpHandler.ProcessRequest(HttpContext context)
        public override void ProcessRequest(HttpContext context)
        {
            var path = context.Request.Url.AbsolutePath.ToLower();
            var path2 = context.Request.Url.AbsoluteUri;
            Uri address8 = new Uri(path);
            if (address8.Scheme == Uri.UriSchemeHttps)
            {

            }
            else
            {
                context.Response.Redirect("");
            }
        }
    }
}