prependHistory method
Implementation
void prependHistory(List<KLineData> values) {
if (values.isEmpty) return;
final previousLength = _data.length;
_data.insertAll(0, values);
_notifyDataChanged(KLineDataChange(
type: KLineDataChangeType.prependHistory,
previousLength: previousLength,
newLength: _data.length,
addedCount: values.length,
));
}