request handler added

[stephanstapel]

I took the recommandation from #17 and did a straight-forward implementation.

I implemented it a simpler manner, not passing the request and response objects. Looking forward to your comments!

[stephanstapel]

The code needs a couple change to make the async hook work. It looks like not all functions that return Task and are named *Async are in fact async in BricklinkClient. Is there a reason for this? Here is an example:

[gebirgslok]

The code needs a couple change to make the async hook work. It looks like not all functions that return Task and are named *Async are in fact async in BricklinkClient. Is there a reason for this? Here is an example:

You can make them async (but don't forget to await the HttpClient call) :)

[gebirgslok]

Thanks for your contribution! I'll release a 1.6.0 version tomorrow 👍