sample.cs

class Program
{
    static void Main(string[] args)
    {
        var someClassInstance = new SomeClass();
        someClassInstance.DoSomething();
    }
}

class Retry : Attribute
{
    private static readonly Policy DefaultRetryPolicy = Policy
        .Handle<Exception>()
        .WaitAndRetry(3, retryAttempt => TimeSpan.FromSeconds(5));

    public void Wrapper(Action action)
    {
        DefaultRetryPolicy.Execute(action);
    }
}

class SomeClass
{
    [Retry]
    public void DoSomething()
    {
        // core logic
    }
}