@NotNull
  public FileTypeAssocTable<T> copy() {
    return new FileTypeAssocTable<>(
      myExtensionMappings,
      myExactFileNameMappings,
      myExactFileNameAnyCaseMappings,
      myConcurrentCharSequenceMapBuilder,
      myHashBangMap,
      myMatchingMappings
    );
  }
@NotNull
  public FileTypeAssocTable<T> copy()