Four ways of Timed HostedServices in .Net 8

1. 'HostedService' - timed with TimeProvider.Timer . . . best choice for Unit Tests
2. 'HostedService' - timed with Timer
3. 'Worker' - timed with Task.Delay
4. 'Worker' - timed with PeriodicTimer

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1. 'HostedService' - timed with TimeProvider.Timer

    This kind of Hosted Service enables Unit Testing without delays.
    Therefore the Unit Tests can run much faster without having to wait.

• Create your Timers with 'timeProvider.CreateTimer(...)' instead of 'new Timer(...)'.
• For Unit Tests simply install NuGet package 'Microsoft.Extensions.TimeProvider.Testing'.
  
• Then inject Microsoft.Extensions.Time.Testing.FakeTimeProvider instead of TimeProvider.System.
• Now you can change the time within your unit tests for example with fakeTimeProvider.Advance(timespan).

2. 'HostedService' - timed with Timer

A traditional Timer is not perfect for unit tests.

3. 'Worker' - timed with Task.Delay

Task.Delay is not perfect for unit tests.

4. 'Worker' - timed with PeriodicTimer

A PeriodicTimer is not perfect for unit tests.