Function sort 

pub fn sort(
    arrivals: &[Triaged],
    ledger: &Ledger,
    newsletters: bool,
    fate: impl Fn(&Triaged) -> Fate,
) -> Sorted

Sorts the inbox’s arrivals of a fetch, as the Porch judged them: those told now, those that wait, those never told (fate: what the matrix of what reaches you says of each now, attention::Attention::decide; and the lanes never told). A message the ledger knows is left out: told once.