Is your feature request related to a problem? Please describe.
Currently, it's not obvious how we can access the raw API key from within a view that's protected behind a permission classes. (This may be useful in order to e.g. fetch resources associated to that key).

Users can access the request headers directly:

scheme, _, key = request.META["HTTP_AUTHORIZATION"].partition("

In #33 we created an ExpandFrom attribute. We now need to go back and add some documentation and usage examples.

You'll definitely want to read #33 and become familiar with the implementation.

Possible Implementation

1. Adding a tutorial for ExpandFrom to docs
   1a. Add a reference to the Documentation list and the table of contents
2. Add a relevant example usage to the NetCoreExampl