code: function RenderManager(generator, config, logger) {
          events.EventEmitter.call(this);
  
          this._generator = generator;
          this._config = config;
          this._logger = logger;
  
          this._svgRenderers = {};
          this._pixmapRenderers = {};
  
          this._componentsByDocument = {};
          this._pending = {};
          this._working = {};
  
          this._renderedAssetCount = 0;
      }
docs: Manages asynchonous rendering jobs across all active documents.
  
  @constructor
  @param {Generator} generator
  @param {object} config
  @param {Logger} logger