RangeDifference rdi = rd[i];
// No change
if (rdi.leftStart() > leftIdx) {
for (int k = leftIdx ; k< rdi.leftStart() ; k++) {
// This just goes straight into the output,
// since it is the same on the left and the right.
// Since it is the same on both side, we handle
// it here (on the left side), and
// ignore it on the right