Dynamically changing data using controller Completed

print("dataSource before $dataSource");
var startIndex=dataSource.indexWhere(
        (element) => element.datetime.millisecondsSinceEpoch >
        list.first.datetime.millisecondsSinceEpoch);

var endIndex=dataSource.indexWhere(
        (element) => element.datetime.millisecondsSinceEpoch >
        list.last.datetime.millisecondsSinceEpoch);
dataSource.replaceRange(startIndex, endIndex, list);

int updatedCount = endIndex - startIndex;
int addedCount = list.length - updatedCount;

List<int> updatedDataIndexes = List.generate(updatedCount+1, (i) => startIndex + i);
List<int> addedDataIndexes = List.generate(addedCount, (i) => startIndex + updatedCount + i+1);
print("updatedDataIndexes $updatedDataIndexes");
print("addedDataIndexes $addedDataIndexes");
print("dataSource after $dataSource");
_controller?.updateDataSource(
  updatedDataIndexes: updatedDataIndexes,
  addedDataIndexes: addedDataIndexes,
);