BackgroundUpdate.cs

using System;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Hosting;

namespace BackgroundUpdate
{
    public class UpdateRunner<T>: IHostedService, IDisposable where T: IUpdate
    {
        private readonly T _inner;
        private readonly TimeSpan _period;
        private Timer? _timer;

        public UpdateRunner(T inner, TimeSpan period)
        {
            _inner = inner;
            _period = period;
        }

        public Task StartAsync(CancellationToken cancellationToken)
        {
            _timer = new Timer(async _ => await _inner.Update(), null, TimeSpan.FromSeconds(1), _period);
            return Task.CompletedTask;
        }

        public Task StopAsync(CancellationToken cancellationToken)
        {
            _timer?.Change(Timeout.Infinite, 0);
            return Task.CompletedTask;
        }
        
        public void Dispose()
        {
            _timer?.Dispose();
        }
    }
}