insertAll method
As List.insertAll.
Implementation
void insertAll(int index, Iterable<E> iterable) {
// Add directly to the underlying `List` then check elements there, for
// performance. Roll back the changes if validation fails.
var safeList = _safeList;
var lengthBefore = safeList.length;
safeList.insertAll(index, iterable);
if (!_needsNullCheck) return;
var insertedLength = safeList.length - lengthBefore;
try {
for (var i = index; i != index + insertedLength; ++i) {
_checkElement(safeList[i]);
}
} catch (_) {
safeList.removeRange(index, index + insertedLength);
rethrow;
}
}