public CustomProblemDetails CustomProblemDetails()
        {
            var problem = new CustomProblemDetails
            {
                StringField = "string field value",
                IntField    = 20
            };

            BadRequest.CopyStandardFieldsTo(problem);
            return(problem);
        }
        public CustomProblemDetails CustomProblemDetailsWithExtensions()
        {
            var problem = new CustomProblemDetails
            {
                StringField = "string field value",
                IntField    = 20,
                Extensions  =
                {
                    { "s2", "value 2" },
                    { "i2",        30 }
                }
            };

            BadRequest.CopyStandardFieldsTo(problem);
            return(problem);
        }