commons chrono.time

---
A point in time, opaque integer milliseconds since Unix epoch.
---
type Timestamp = opaque Int where NonNegative

fn Timestamp.equals(self, other: Timestamp) -> Bool {
  self == other
}

fn Timestamp.before(self, other: Timestamp) -> Bool {
  self.raw < other.raw
}

fn Timestamp.after(self, other: Timestamp) -> Bool {
  self.raw > other.raw
}
