Used to specify HTTP parameters that should be sent with the outbound request.
When this annotation is placed at the interface level of a REST client interface, the specified headers will be sent on each request for all
methods in the interface.
When this annotation is placed on a method, the headers will be sent only for that method. If the same HTTP header is specified in an annotation
for both the type and the method, only the header value specified in the annotation on the method will be sent.