Has anybody set up Web API 2 Attribute Routing with 8.2 or later? I tried the 'official' route, which is to create a custom pipeline handler to the initialize pipeline that does the registration. I've tried to hook it up with a config as well as using webactivator. I've done something similar to this: http://wp-bartbovendeerdtcom.azurewebsites.net/sitecore-8-webapi-v2-mvc-and-attribute-routing/ - In both cases, I get an error
"A route named 'MS_attributerouteWebApi' is already in the route collection".
I've also used a marketplace module (https://marketplace.sitecore.net/Modules/A/Attribute_Routing_Support.aspx?sc_lang=en), which is essentially the same thing, but hooked up with a config. All same error.
It makes me think that a web api registration is happening somewhere else already in Sitecore registrations, but I'm not sure where. Even if it does, how do I get past this?