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
```
}
          throw readyReason;
        });
      };
    });
    messageHandler.on("ReaderHeadersReady", data => {
      const headersCapability = createPromiseCapability();
      const fullReader = this._fullReader;
      fullReader.headersReady.then(() => {
        
        
        if (!fullReader.isStreamingSupported || !fullReader.isRangeSupported) {
          if (this._lastProgress && loadingTask.onProgress) {
            loadingTask.onProgress(this._lastProgress);
          }
          fullReader.onProgress = evt => {
            if (loadingTask.onProgress) {
              loadingTask.onProgress({
                loaded: evt.loaded,
                total: evt.total,
              });
            }
          };
        }
        headersCapability.resolve({
          isStreamingSupported: fullReader.isStreamingSupported,
          isRangeSupported: fullReader.isRangeSupported,
          contentLength: fullReader.contentLength,
        });
      }, headersCapability.reject);