Constant FUTURE 

const FUTURE: i64 = _; // 600i64

How far ahead of this device’s clock another device’s times may run and still be taken (ten minutes: a clock left to drift; one set wrong by hours or a year is not): beyond it, its copy is no news and is set aside (Peer::set_aside): nothing it says counts, nor a word it gives, and its doubt says its clock runs ahead (the ninth review’s F1; the final review’s F1H).