Function negotiated 

pub fn negotiated<T, Formats>(
    value: T,
    accept: AcceptHeader,
) -> NegotiatedResponse<T, Formats>

Wrap a domain value for content negotiation with the given Accept header.

Example

async fn get_user(accept: AcceptHeader) -> NegotiatedResponse<User, (JsonFormat, TextFormat)> {
    negotiated(user, accept)
}