Add support for IHostedLifecycleService in WebHost

[jraufeisen]

Is there an existing issue for this?

• I have searched the existing issues

Describe the solution you'd like

.NET 8 introduced the interface IHostedLifecycleService, which extends IHostedService with some additional callbacks such as StartingAsync() and StartedAsync(). The original API proposal (dotnet/runtime#86511) noted that

This interface is located in the Microsoft.Extensions.Hosting.Abstractions assembly which will be supported by the default host (in the Microsoft.Extensions.Hosting assembly). Other hosts will need to implement IHostedService in order to support this new interface.

As far as I can see, WebHost did not gain support for this new feature yet.

aspnetcore/src/Hosting/Hosting/src/Internal/WebHost.cs

Lines 22 to 30 in 6d1573a

	internal sealed partial class WebHost : IWebHost, IAsyncDisposable
	{
	private const string DeprecatedServerUrlsKey = "server.urls";
	private readonly IServiceCollection _applicationServiceCollection;
	private IStartup? _startup;
	private ApplicationLifetime? _applicationLifetime;
	private HostedServiceExecutor? _hostedServiceExecutor;

aspnetcore/src/Hosting/Hosting/src/Internal/HostedServiceExecutor.cs

Lines 8 to 47 in 6d1573a

	internal sealed class HostedServiceExecutor
	{
	private readonly IEnumerable<IHostedService> _services;
	public HostedServiceExecutor(IEnumerable<IHostedService> services)
	{
	_services = services;
	}
	public async Task StartAsync(CancellationToken token)
	{
	foreach (var service in _services)
	{
	await service.StartAsync(token);
	}
	}
	public async Task StopAsync(CancellationToken token)
	{
	List<Exception>? exceptions = null;
	foreach (var service in _services)
	{
	try
	{
	await service.StopAsync(token);
	}
	catch (Exception ex)
	{
	exceptions ??= [];
	exceptions.Add(ex);
	}
	}
	// Throw an aggregate exception if there were any exceptions
	if (exceptions != null)
	{
	throw new AggregateException(exceptions);
	}
	}

Would it be possible to add support for IHostedLifecycleService to WebHost?