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._totalLength + this.length;
  }
  addOp(fn, args) {
    this.optimizer.push(fn, args);
    this.weight++;
    if (this._streamSink) {
      if (this.weight >= OperatorList.CHUNK_SIZE) {
        this.flush();
      } else if (
        this.weight >= OperatorList.CHUNK_SIZE_ABOUT &&
        (fn === OPS.restore || fn === OPS.endText)
      ) {
        
        this.flush();
      }
    }
  }
  addDependency(dependency) {
    if (this.dependencies.has(dependency)) {
      return;
    }
    this.dependencies.add(dependency);
    this.addOp(OPS.dependency, [dependency]);
  }
  addDependencies(dependencies) {