docs: @SuppressWarnings("unchecked")
  	public static <K, V> Map<K, V> fieldValueMap(Iterator<V> iter, String fieldName) {
  		final Map<K, V> result = new HashMap<>();
  		if (null != iter) {
  			V value;
  			while (iter.hasNext()) {
  				value = iter.next();
  				result.put((K) ReflectUtil.getFieldValue(value, fieldName), value);
  			}
  		}
  		return result;
  	}