Function resolved 

pub fn resolved(
    server: &Server,
    session: &mut Session,
    spec: Option<&'static Spec>,
    args: Args<'_>,
    out: &mut Out,
) -> Flow

The same, for a caller that has already found the command.

The engine frames a command before it runs it, and between those two it also asks which key the command touches so the record can be prefetched. That is two more chances to look the name up, and looking it up three times to run it once is three times the cost of the cheapest thing in the path. So the engine resolves the name where it frames the command, carries the answer on the framed command, and both the other two take it from there.

spec is None for a name that is not a command, which is the same thing lookup says and lands in the same reply.