private void putInternal(@NonNls @NotNull Object key, Object value) {
    if (singleKey == null && myMap == null) {
      singleKey = key;
      singleValue = value;
    }
    else {
      if (myMap == null) {
        myMap = new HashMap<>(1);
        myMap.put(singleKey, singleValue);

        singleKey = null;
        singleValue = null;
      }

      myMap.put(key, value);
    }
  }
private void putInternal(@NonNls @NotNull Object key, Object value)