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
```
if (!params || !params.port) {
        throw new Error("PDFWorker.fromPort - invalid method signature.");
      }
      if (pdfWorkerPorts.has(params.port)) {
        return pdfWorkerPorts.get(params.port);
      }
      return new PDFWorker(params);
    }
    static getWorkerSrc() {
      return getWorkerSrc();
    }
  }
  return PDFWorker;
})();
/**
 * For internal use only.
 * @ignore
 */
class WorkerTransport {