Configuration:
- PDF.js version: 2.0.550

Steps to reproduce the problem:
1. Render document in SVG mode `renderMode="svg"`

What is the expected behavior? (add screenshot)
Rendering annotations same way as they rendered on canvas

What went wrong? (add screenshot)
```
Warning: Unimplemented operator beginAnnotations
Warning: Unimplemented operator endAnnotations
```
return this._transport.startCleanup(keepLoadedFonts || this.isPureXfa);
  }
  /**
   * Destroys the current document instance and terminates the worker.
   */
  destroy() {
    return this.loadingTask.destroy();
  }
  /**
   * @type {DocumentInitParameters} A subset of the current
   *   {DocumentInitParameters}, which are needed in the viewer.
   */
  get loadingParams() {
    return this._transport.loadingParams;
  }
  /**
   * @type {PDFDocumentLoadingTask} The loadingTask for the current document.
   */
  get loadingTask() {
    return this._transport.loadingTask;
  }
  /**
   * @returns {Promise<Uint8Array>} A promise that is resolved with a
   *   {Uint8Array} containing the full data of the saved document.
   */
  saveDocument() {