constructor(name, entryType, startTime, duration) {
            this.name = name;
            this.entryType = entryType;
            this.startTime = startTime;
            this.duration = duration;
        }
The PerformanceEntry object encapsulates a single performance metric
that is part of the browser's performance timeline.

This is an object returned by the `mark` and `measure` methods on the Performance prototype