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.getData();
  }
  /**
   * @returns {Promise<{ length: number }>} A promise that is resolved when the
   *   document's data is loaded. It is resolved with an {Object} that contains
   *   the `length` property that indicates size of the PDF data in bytes.
   */
  getDownloadInfo() {
    return this._transport.downloadInfoCapability.promise;
  }
  /**
   * @typedef {Object} PDFDocumentStats
   * @property {Object<string, boolean>} streamTypes - Used stream types in the
   *   document (an item is set to true if specific stream ID was used in the
   *   document).
   * @property {Object<string, boolean>} fontTypes - Used font types in the
   *   document (an item is set to true if specific font ID was used in the
   *   document).
   */
  /**
   * @returns {Promise<PDFDocumentStats>} A promise this is resolved with
   *   current statistics about document structures (see
   *   {@link PDFDocumentStats}).
   */
  getStats() {