updateHorizontalOffset method
Updates the horizontal scroll offset controller.
Replaces the current horizontal offset with a new one, properly managing listeners to ensure scroll changes trigger updates.
Implementation
void updateHorizontalOffset(ViewportOffset offset) {
if (horizontal != offset) {
horizontal.removeListener(_onScrollOffsetChanged);
horizontal = offset;
if (attached) {
horizontal.addListener(_onScrollOffsetChanged);
}
}
}