addGroup method
Sets the values in accordance with the specified group
and increases
(if required) the length up to (range.end + 1).
Implementation
void addGroup(GroupedRangeList<E> group) {
if (_fixedLength) {
throw StateError('Unable to add the group into fixed list.');
}
if (frozen) {
_errorModificationNotAllowed();
}
if (group.start < 0) {
throw RangeError(group.start);
}
_setGroup(group);
if (_length < group.end + 1) {
_length = group.end + 1;
}
}