Returns the global performance Object if available, which can be used to
gather performance information about the current document. It serves as the
point of exposure for the Performance Timeline API, the High Resolution Time
API, the Navigation Timing API, the User Timing API, and the Resource Timing API.
Returns the global
performanceObject if available, which can be used to gather performance information about the current document. It serves as the point of exposure for the Performance Timeline API, the High Resolution Time API, the Navigation Timing API, the User Timing API, and the Resource Timing API.