public @NotNull FrozenDocument applyEvent(@NotNull DocumentEvent event, int newStamp) {
    int offset = event.getOffset();
    int oldEnd = offset + event.getOldLength();
    ImmutableCharSequence newText = myText.replace(offset, oldEnd, event.getNewFragment());
    LineSet newLineSet = getLineSet().update(myText, offset, oldEnd, event.getNewFragment(), event.isWholeTextReplaced());
    return new FrozenDocument(newText, newLineSet, newStamp, null);
  }
public @NotNull FrozenDocument applyEvent(@NotNull DocumentEvent event, int newStamp)