queryIndexedColor method
Implementation
@override
void queryIndexedColor(int index) {
if (index < 0 || index > 255) return;
final color = _indexedColorOverrides[index] ?? onColorQuery?.call(4, index);
if (color == null) return;
onOutput?.call('\x1b]4;$index;${_formatOscColor(color)}\x1b\\');
}