chore: import upstream snapshot with attribution

packages/core/src/v3/clock/clock.ts

@@ -0,0 +1,20 @@
+/**
+ * Contains two parts: the first part is the seconds, the second part is the nanoseconds.
+ *
+ */
+export type ClockTime = [number, number];
+
+export interface Clock {
+  preciseNow(): ClockTime;
+  reset(): void;
+}
+
+export function calculateDurationInMs(start: ClockTime, end: ClockTime): number {
+  const [startSeconds, startNanoseconds] = start;
+  const [endSeconds, endNanoseconds] = end;
+
+  const seconds = endSeconds - startSeconds;
+  const nanoseconds = endNanoseconds - startNanoseconds;
+
+  return Math.floor(seconds * 1000 + nanoseconds / 1000000);
+}