the accept header code example
Example: accept header in api
`Accept Header` can be used to ask the server to return
different type of response format
For example :
`/api/xname` endpoint , support both xml and json
as response type so we can add accept header `application/xml`
to get xml result and `application/json` result.
If server does not support such type ,
it will return `406`(not acceptable) status code.