Some services are not able to be constructed (Error while validating the service descriptor 'ServiceType: MediatR.IRequestHandler code example

Example: Some services are not able to be constructed (Error while validating the service descriptor 'ServiceType: Microsoft.Extensions.Hosting.IHostedService Lifetime: Singleton ImplementationType:

public class MySingletonService
{
    private IServiceScopeFactory Services { get; }
    
    public MySingletonService(IServiceScopeFactory services)
    {
        Services = services;
    }
    
    public void DoSomethingWithScopedService()
    {
        using (var scope = Services.CreateScope())
        {
            var myScopedService = scope.GetRequiredService<IScopedService>();
            // ... Use the service here ...
        }
    }
}