title: Documenting message based API in Swagger or RAML
body: <p>How do we document a message based API in Swagger or RAML ?
  By message based I mean that the endpoint is always the same, but one can send multiple message types to this endpoint and depending on the type of input message we get different responses.
  Is there an example of this type of API I can have look ?</p>
  
  <p>Thank you.
   Luis Oscar </p>