Microsoft.Extensions.DependencyInjection debug experience could be improved.

I think there are two primary APIs to focus on: ServiceCollection and IServiceProvider implementations.

ServiceCollection is already pretty good. It could be improved with a debugger display that shows the count and whether it's read-only.

IServiceProvider is difficult to debug. Useful information to make available:

• Its service descriptors (the information that ServiceCollection displays)
• Is it a scoped or root service provider
• Is it disposed
• Realized services
• Registered disposable services
• More that I haven't thought of?