code: function ResponsiveImage() {
    if (!(this instanceof ResponsiveImage)) {
      return new ResponsiveImage();
    }
  
    this.element = null;
    this.loadedSizes = {};
    this.knownSizes = [];
    this.currentBreakpoint = null;
    this.src = null;
    this.isFlexible = false;
    this.hasRetina = false;
    this.preserveAspectRatio = false;
    this.knownDimensions = null;
    this.hasLoaded = false;
    this.hasRunOnce = false;
    this.hasLoadedFallback = false;
  }
docs: Ghetto Record implementation.