Constant ALTO_PROPMAP_JSON 

pub const ALTO_PROPMAP_JSON: Mime;

[RFC9240]

let media = mime2::application::ALTO_PROPMAP_JSON;
assert_eq!(media.ttype, "application");
assert_eq!(media.subtype, "alto-propmap+json");
assert_eq!(media.to_string(), "application/alto-propmap+json");