Endpoints are slowed down due to high latency on preflight requests #570
Description
As you can see here, a 3 consequent calls to res.bitcoin.com could take up to 5 seconds which is a bad UX for web applications using it. Most of this time is not spent on real request but on preflight request which browsers send before the real request to make sure the endpoint is accepting that content-type.
You can see below that these requests (OPTION method) are taking around 3 seconds
