public ExpressionBuilder(HateoasRegistration <TModel> registration)
 {
     _registration            = registration;
     _registration.Expression = _expression = HateoasExpression <TModel> .Create(registration);
 }
 internal static void SetMethod <TController>(this HateoasExpression expression, HttpMethod method, LambdaExpression actionSelector) where TController : IHttpController
 {
     expression.Controller = typeof(TController);
     expression.HttpMethod = method;
     expression.Action     = actionSelector;
 }