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.messageHandler.sendWithPromise("GetMarkInfo", null);
  }
  getStats() {
    return this.messageHandler.sendWithPromise("GetStats", null);
  }
  async startCleanup(keepLoadedFonts = false) {
    await this.messageHandler.sendWithPromise("Cleanup", null);
    if (this.destroyed) {
      return; 
    }
    for (let i = 0, ii = this.pageCache.length; i < ii; i++) {
      const page = this.pageCache[i];
      if (!page) {
        continue;
      }
      const cleanupSuccessful = page.cleanup();
      if (!cleanupSuccessful) {
        throw new Error(`startCleanup: Page ${i + 1} is currently rendering.`);
      }
    }
    this.commonObjs.clear();
    if (!keepLoadedFonts) {
      this.fontLoader.clear();
    }
    this._hasJSActionsPromise = null;
  }
  get loadingParams() {