/**
  * Returns an instance that encapsulates the given [Throwable] [exception] as failure.
  */
 public static Result <T> Failure(Exception exception) =>
 new Result <T>(ResultExt.CreateFailure <T>(exception));
 /**
  * Returns an instance of loading.
  */
 public static Result <T> Loading() =>
 new Result <T>(ResultExt.GetLoading());