code: public BoxRequestsFile.DownloadFile getDownloadAvatarRequest(OutputStream outputStream, String userId) {
          BoxRequestsFile.DownloadFile request = new BoxRequestsFile.DownloadFile(userId, outputStream, getAvatarDownloadUrl(userId), mSession);
          return request;
      }
docs: Gets a request that downloads the given avatar to the provided outputStream. Developer is responsible for closing the outputStream provided.
  
  @param outputStream outputStream to write file contents to.
  @param userId the file id to download.
  @return  request to download a file thumbnail