pub fn is_attr_marked_with(name: &str, marker: Key<bool>) -> Option<bool>Expand description
Returns Some(true) when the declared attribute key with this
name carries the given bool meta marker with value true,
Some(false) when it carries the marker with value false, and
None for unknown names or declared keys that do not carry the
marker at all.
Generic “is this attr a member of the category declared by this
marker?” primitive. The lower layer does not know what category
the marker names — the caller supplies the category marker that
defines its vocabulary (e.g. ATTRIBUTION_HEADER for attribution
data carried on envelope headers).