docs: private static String convertStreamToString(InputStream inputStream)
          throws IOException {
          if (inputStream == null) {
              return "";
          } else {
              StringBuilder stringBuilder = new StringBuilder();
              String line;
              try {
                  BufferedReader reader =
                      new BufferedReader(new InputStreamReader(inputStream,
                                                               StringUtils.UTF8));
                  while ((line = reader.readLine()) != null) {
                      stringBuilder.append(line);
                  }
              } finally {
                  inputStream.close();
              }
              return stringBuilder.toString();
          }
      }