code: public long getSoFar(final int downloadId) {
          BaseDownloadTask.IRunningTask task = FileDownloadList.getImpl().get(downloadId);
          if (task == null) {
              return FileDownloadServiceProxy.getImpl().getSofar(downloadId);
          }
  
          return task.getOrigin().getLargeFileSoFarBytes();
      }
docs: Get downloaded bytes so far by the downloadId.