Unable to see OData API under swagger documentation

Hi,
We are having OData API in our application for which we are using swagger documentation. We are registering OData routing in WebAPI.config in our application start event(global.asax). After that in same WebAPI.config register event we are registering swagger documentation. Previously it is working fine but due to some performance issue we are trying to register oData routing asynchronously in background thread. So routing registration works fine but now we are unable to see swagger documentation for that API. Is anything we are missing.