Conventional middleware class requirements.

[serpent5]

Fixes #11443.

I made a few changes here:

• Changed the delegate example to use async/await to match the approach used in the middleware class.
• Switched the example URL to use https and the template-generated default 5001 port for that.
• Added an explanation of the requirements for a middleware class. All of these requirements are enforced by the hosting startup process, where exceptions are thrown if the requirements aren't met.
• Moved the dependencies section up to below the requirements explanation I added. I think this follows on naturally.
• Made the per-request dependencies section a child of the higher-level dependencies section.

TODO:

I don't know how to test the moniker ranges locally, so I couldn't update the note about InvokeAsync being available in ASP.NET Core 2.0+. Ideally, I'd like to know how to test this locally but alternatively, please make the relevant change. I imagine this being a different version of the relevant bullet for < 2.0, e.g.:

A public method named Invoke. In ASP.NET Core 2.0 or later, the name can also be InvokeAsync. This method must:

[guardrex]

Nice work ...

Update the ms.date on Line 7.

[guardrex]

One more nit.

[guardrex]

I don't know how to test the moniker ranges locally

Version the whole topic for 2.1+ (1.1 is about to go away, and 2.0 has already left the scene).

In the metadata between description and ms.author, place this line ...

monikerRange: '>= aspnetcore-2.1'

[serpent5]

@guardrex Thanks for such prompt feedback. 🚀

I've (hopefully) made the relevant changes, as requested.

[guardrex]

❤️ I'm lov'in IT!™️

"I'm lov'in IT!" is a registered trademark of the McDonald's Corporation. 😄

[guardrex]

Let's go ahead and not disturb cats OOF. 🏖