Access ILogger during service registration

Question

I'm trying to register something on IServiceCollection during startup of my .NET 6 application:

public static class SomeRegistrationExtensions
{
  public static IServiceCollection RegisterSomething(
    this IServiceCollection services
  )
  {
    var sp = services.BuildServiceProvider();
    var logger = sp.GetService<ILogger>();
    
    logger.Log(
      LogLevel.Warning,
      "Nothing gets registered here..."
    );
    return services;
  }
}

My Program.cs is picking up the registration:

using AspNetCoreLoggerInServiceRegistration.Registrations;

var builder = WebApplication.CreateBuilder(args);
builder.Logging.ClearProviders();
builder.Logging.AddConsole();
builder.Services.RegisterSomething();

However, ILogger doesn't seem to be available:

Unhandled exception. System.ArgumentNullException: Value cannot be null. (Parameter 'logger')
   at Microsoft.Extensions.Logging.LoggerExtensions.Log(ILogger logger, LogLevel logLevel, EventId eventId, Exception exception, String message, Object[] args)
   at Microsoft.Extensions.Logging.LoggerExtensions.Log(ILogger logger, LogLevel logLevel, String message, Object[] args)
   at AspNetCoreLoggerInServiceRegistration.Registrations.SomeRegistrationExtensions.RegisterSomething(IServiceCollection services) in /SomeRegistrationExtensions.cs:line 12
   at Program.<Main>$(String[] args) in Program.cs:line 6

I created a repro on GitHub.