DataService.cs

using System.Collections.Generic;
using System.Threading;
using Microsoft.Extensions.Logging;

namespace DecoratorPattern.Services
{
    public class DataService : IDataService
    {
        private readonly ILogger<DataService> _logger;

        public DataService(ILogger<DataService> logger)
        {
            _logger = logger;
        }
        
        public List<int> GetData()
        {
            var data = new List<int>();

            for (var i = 0; i < 10; i++)
            {
                _logger.LogInformation("Log something");
                
                data.Add(i);

                Thread.Sleep(350);
            }

            return data;
        }
    }
}