Object containing metrics as key/value pairs.

• Timestamp : The timestamp when the metrics sample was taken.

• Documents : Number of documents in the page.

• Frames : Number of frames in the page.

• JSEventListeners : Number of events in the page.

• Nodes : Number of DOM nodes in the page.

• LayoutCount : Total number of full or partial page layout.

• RecalcStyleCount : Total number of page style recalculations.

• LayoutDuration : Combined durations of all page layouts.

• RecalcStyleDuration : Combined duration of all page style recalculations.

• ScriptDuration : Combined duration of JavaScript execution.

• TaskDuration : Combined duration of all tasks performed by the browser.

• JSHeapUsedSize : Used JavaScript heap size.

• JSHeapTotalSize : Total JavaScript heap size.