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[ashercoren]

This library looks awesome, but with the luck of Wiki it's very difficult to understand how to use it (I'm referring to the more complex features, such as custom middleware, custom headers, etc.

[puppybits]

I got stuck a bit too. But it's using standard ring requests so much of the documentation about Ring applies to this library as well.
https://github.com/ring-clojure/ring/wiki/Concepts

For instead setting customs headers can be done like this:

(http/post my-uri {
      :headers {"Content-Type" "application/json"}
      :body {:token "my-token"}})