interface PerformanceLongTaskTiming : PerformanceEntry {
  [SameObject, SaveSameObject] readonly attribute FrozenArray<TaskAttributionTiming> attribution;
};

interface TaskAttributionTiming : PerformanceEntry {
  readonly attribute DOMString containerType;
  readonly attribute DOMString containerSrc;
  readonly attribute DOMString containerId;
  readonly attribute DOMString containerName;
};

var observer = new PerformanceObserver(function(list) {
  var perfEntries = list.getEntries();
  for (var i = 0; i < perfEntries.length; i++) {
     // Process long task notifications:
     // report back for analytics and monitoring
     // ...
  }
});


// register observer for long task notifications
observer.observe({entryTypes: ["longtask"]});

// Long script execution after this will result in queueing 
// and receiving “longtask” entries in the observer.

interfacePerformanceEventTiming: PerformanceEntry {// The type of event dispatched. E.g. "touchmove".// Doesn't require an event listener of this type to be registered.
    readonly attribute DOMString name;// "event".
    readonly attribute DOMString entryType;// The event timestamp.
    readonly attribute DOMHighResTimeStamp startTime;// The time the first event handler started to execute.// |startTime| if no event handlers executed.
    readonly attribute DOMHighResTimeStamp processingStart;// The time the last event handler finished executing.// |startTime| if no event handlers executed.
    readonly attribute DOMHighResTimeStamp processingEnd;// The duration between |startTime| and the next time we "update the rendering // or user interface of that Document and its browsing context to reflect the // current state" in step 7.12 in the HTML event loop processing model.
    readonly attribute DOMHighResTimeStamp duration;// Whether or not the event was cancelable.
    readonly attribute boolean cancelable;};// Contains the number of events which have been dispatched, per event type.interfaceEventCounts{
  readonly attribute unsigned long click;...
  readonly attribute unsigned long touchmove;...};

partial interfacePerformance{// Contains the number of events which have been dispatched, per event type. Populated asynchronously. 
    readonly attribute EventCounts eventCounts;};

const performanceObserver = new PerformanceObserver((entries) => {
  for (const entry of entries.getEntries()) {
      console.log(entry);
  }
});

performanceObserver.observe({entryTypes:['event']});