PerformanceTrack.js

const track = new PerformanceTrack();

// At some point
track.mark(name);

// At some other point
track.mark(name);

// Combines mark->mark as a single entry with duration
track.measure(name);

// Gives devtools additional information about this track
console.describeTrack(track, { color: "blue", track: "framework" });

const observer = new PerformanceObserver(entries => {
    for (const loaf : entries.getEntriesByType("long-animation-frame") {
      // This will have all the marks&measures from the attached tracks
      loaf.tracks
      
      // This will have now also include functions captured with track.bind
      loaf.scripts
    }
});
observer.observe({entryType: "long-animation-frame"});
observer.attachTrack(track);