constructor(rendition) {
    this.rendition = rendition;
    this.highlights = [];
    this.underlines = [];
    this.marks = [];
    this._annotations = {};
    this._annotationsBySectionIndex = {};
    this.rendition.hooks.render.register(this.inject.bind(this));
    this.rendition.hooks.unloaded.register(this.clear.bind(this));
  }
Handles managing adding & removing Annotations
@param {Rendition} rendition
@class