code: public static String getFirstHeader(String headerName, HttpResponse httpResponse) {
          Header header = httpResponse.getFirstHeader(headerName);
          if (header != null) {
              return header.getValue();
          }
          return null;
      }
docs: Get the value of the first header matching "headerName".
  
  @param headerName
  @param httpResponse
  @return value of the first header or null if it doesn't exist.