docs: public static Map<String, String> extractFromPropertiesAsMap(String prefix, Properties properties) {
          Map<String, String> ret = new HashMap<>();
          Enumeration names = properties.propertyNames();
          String prefixP = prefix + ".";
          while (names.hasMoreElements()) {
              String propName = (String) names.nextElement();
              if (propMatchesPrefix(prefixP, propName)) {
                  String mapKey = propName.substring(prefixP.length());
                  if(PROPERTY_COMBINE_POLICY_SUFFIX.equals(mapKey)) {
                      continue;
                  }
  
                  ret.put(mapKey, properties.getProperty(propName));
              }
          }
          return ret.size() > 0 ? ret : null;
      }