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
```
length,
    initialData,
    progressiveDone = false,
    contentDispositionFilename = null
  ) {
    this.length = length;
    this.initialData = initialData;
    this.progressiveDone = progressiveDone;
    this.contentDispositionFilename = contentDispositionFilename;
    this._rangeListeners = [];
    this._progressListeners = [];
    this._progressiveReadListeners = [];
    this._progressiveDoneListeners = [];
    this._readyCapability = createPromiseCapability();
  }
  addRangeListener(listener) {
    this._rangeListeners.push(listener);
  }
  addProgressListener(listener) {
    this._progressListeners.push(listener);
  }
  addProgressiveReadListener(listener) {
    this._progressiveReadListeners.push(listener);
  }
  addProgressiveDoneListener(listener) {