If GetModelAsync takes too long to complete, requests will fail.

[rayao]

Since GetModelAsync is asynchronous, if it takes too long, RESTier routing won't get registered in time and all requests before the registration done will fail.
Also, in test runs sometimes 2 or more test methods run simultaneously, which leads to GetModelAsync called simultaneously for a same Api, the model pipeline will throw for lacking synchronization mechanism. I think this could be triggered in production when 2 services expose a same Api.

[rayao]

Working on a partial fix not including long running (real async) GetModelAsync.

[rayao]

Fixed with fc09f71
In WebApi publisher, async nature of model pipeline is ignored.
I left MapRestierRoute method signature unchanged in case later WebApi supports async initialization.