Function now_ms 

pub fn now_ms() -> u64

Milliseconds since the epoch, clamped rather than panicking on a clock before it. The one clock every durable record here is stamped with — created_ms, updated_ms, a cancel marker’s requested_ms, a message’s created_ms — and what a host rendering one of those alongside its own notion of “now” (basis list’s own age column, for one) should read now from, so the two clocks cannot disagree about the epoch.