private @NotNull ValueContainerMap<Key, Value> createValueContainerMap() throws IOException {
    ValueContainerExternalizer<Value> valueContainerExternalizer = new ValueContainerExternalizer<>(myDataExternalizer, myInputRemapping);
    PersistentMapBase<Key, UpdatableValueContainer<Value>> persistentMap = createPersistentMap(myKeyDescriptor,
                                                                                               valueContainerExternalizer,
                                                                                               myReadOnly,
                                                                                               compactOnClose(),
                                                                                               myKeyIsUniqueForIndexedFile);

    return new ValueContainerMap<>(persistentMap,
                                   myKeyDescriptor,
                                   myDataExternalizer,
                                   myKeyIsUniqueForIndexedFile);
  }
private @NotNull ValueContainerMap<Key, Value> createValueContainerMap()