splitImmutable method
Implementation
(Rope, Rope) splitImmutable(int position) {
if (position < 0 || position > length) {
throw RangeError('Invalid position: $position for length $length');
}
return (
Rope._fromRoot(_root.range(0, position), _selection),
Rope._fromRoot(_root.range(position, length), _selection),
);
}