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1export interface Clock {
2 /**
3 * Return the current time in milliseconds from some epoch such as the Unix epoch or process start
4 */
5 now(): number;
6}
7/**
8 * A utility for returning wall times anchored to a given point in time. Wall time measurements will
9 * not be taken from the system, but instead are computed by adding a monotonic clock time
10 * to the anchor point.
11 *
12 * This is needed because the system time can change and result in unexpected situations like
13 * spans ending before they are started. Creating an anchored clock for each local root span
14 * ensures that span timings and durations are accurate while preventing span times from drifting
15 * too far from the system clock.
16 *
17 * Only creating an anchored clock once per local trace ensures span times are correct relative
18 * to each other. For example, a child span will never have a start time before its parent even
19 * if the system clock is corrected during the local trace.
20 *
21 * Heavily inspired by the OTel Java anchored clock
22 * https://github.com/open-telemetry/opentelemetry-java/blob/main/sdk/trace/src/main/java/io/opentelemetry/sdk/trace/AnchoredClock.java
23 */
24export declare class AnchoredClock implements Clock {
25 private _monotonicClock;
26 private _epochMillis;
27 private _performanceMillis;
28 /**
29 * Create a new AnchoredClock anchored to the current time returned by systemClock.
30 *
31 * @param systemClock should be a clock that returns the number of milliseconds since January 1 1970 such as Date
32 * @param monotonicClock should be a clock that counts milliseconds monotonically such as window.performance or perf_hooks.performance
33 */
34 constructor(systemClock: Clock, monotonicClock: Clock);
35 /**
36 * Returns the current time by adding the number of milliseconds since the
37 * AnchoredClock was created to the creation epoch time
38 */
39 now(): number;
40}
41//# sourceMappingURL=anchored-clock.d.ts.map
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