docs: public static String getHeader(Map<String, List<String>> responseHeaders, String header) {
          if (responseHeaders == null) {
              return null;
          }
          // Search the headers case insensitive (headers should be evaluated as
          // case insensitive, but, the Swagger implementation uses HashMap that
          // is case sensitive)
          for (Map.Entry<String, List<String>> entry : responseHeaders.entrySet()) {
              if (entry.getKey().equalsIgnoreCase(header)) {
                  List<String> headersList = entry.getValue();
                  if (headersList != null && !headersList.isEmpty()) { // Better
                                                                       // safe
                                                                       // than
                                                                       // sorry
                      return headersList.get(0);
                  }
                  break; // Header found, but, was null or empty
              }
          }
          return null;
      }