Constant http::header::EXPIRES

pub const EXPIRES: HeaderName = HeaderName{inner: Repr::Standard(StandardHeader::Expires),}

Contains the date/time after which the response is considered stale.

Invalid dates, like the value 0, represent a date in the past and mean that the resource is already expired.

If there is a Cache-Control header with the "max-age" or "s-max-age" directive in the response, the Expires header is ignored.