How to measure the performance of async operations?

1.	How to measure the performance of async operations?
Answer» Performance API provides us with tools to FIGURE out the necessary performance metrics. A simple EXAMPLE would be: CONST { PerformanceObserver, performance } = require('perf_hooks');const obs = new PerformanceObserver((items) => { console.log(items.getEntries()[0].DURATION); performance.clearMarks();});obs.observe({ entryTypes: ['measure'] });performance.measure('Start to Now');performance.mark('A');doSomeLongRunningProcess(() => { performance.measure('A to Now', 'A'); performance.mark('B'); performance.measure('A to B', 'A', 'B');});

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