Expose InMemoryTransportFactory as a public API

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Is your feature request related to a problem? Please describe the problem.

Unit Testing AspNetCore, run unit tests without creating a socket. Which would likely make it harder to run concurrent tests on a CI server.

### Describe the solution you'd like

Being able to run AspNetCore Kestrel completely in memory.

### Additional context

_No response_