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.xfaFactory && this.xfaFactory.isValid();
  }
  get htmlForXfa() {
    if (this.xfaFactory) {
      return this.xfaFactory.getPages();
    }
    return null;
  }
  async loadXfaImages() {
    const xfaImagesDict = await this.pdfManager.ensureCatalog("xfaImages");
    if (!xfaImagesDict) {
      return;
    }
    const keys = xfaImagesDict.getKeys();
    const objectLoader = new ObjectLoader(xfaImagesDict, keys, this.xref);
    await objectLoader.load();
    const xfaImages = new Map();
    for (const key of keys) {
      const stream = xfaImagesDict.get(key);
      if (!isStream(stream)) {
        continue;
      }
      xfaImages.set(key, stream.getBytes());
    }
    this.xfaFactory.setImages(xfaImages);
  }
  async loadXfaFonts(handler, task) {