Struct Keys 

struct Keys {
    track_alias: Option<u64>,
    group_id: u64,
    subgroup_id: Option<u64>,
    object_id: u64,
    priority: Option<u8>,
}

The keys one unit carries, whichever carrier it arrived on.

The argument to Matcher::claims, and the reason a datagram and a framed object can be answered by one conjunction. Two of the five differ between the carriers and the difference is the type’s whole content: a fetch object carries no track alias and a datagram carries no subgroup ID.

Fields

track_alias: Option<u64>

group_id: u64

subgroup_id: Option<u64>

object_id: u64

priority: Option<u8>