I'm writing an app that looks at a Content-Type (e.g. `application/json`) to determine processing. Most of the time, the Content-Type is well known. However, sometimes it would be convenient to create a custom Content-Type (e.g. `application/swagger' or`text/raml' or yaml/raml'). What are the ramifications of creating a custom Content-Type? How do browsers deal with them if I want to send them as an HTTP response? Does it matter whether I use `text/swagger` or `application/swagger`?