Type Alias MonotonicNowFn 

pub type MonotonicNowFn = fn() -> u64;

v7.17.0 Phase 2.3 — monotonic time source for deadline-aware cancellation (PG statement_timeout). Returns microseconds since some host-stable monotonic origin (typically the first call into Instant::now() on the server). The engine never calls Instant::now() directly so the crate stays #![no_std].