code: @Override
      public Map<String, List<String>> getHeaders() {
          final Map<String, List<String>> headerMap = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
          final HttpHeaders headers = ahcResponse.getHeaders();
          for (String name : headers.names()) {
              final List<String> values = headers.getAll(name);
              headerMap.put(name, values);
          }
          return headerMap;
      }
docs: Get all the HTTP headers of the response as a case-insensitive map