private int removeAllTo(Address toAddr) throws IOException {
		RefList toRefs = getToRefs(toAddr);
		if (toRefs == null) {
			return 0;
		}
		int cnt = toRefs.getNumRefs();
		Reference[] refs = toRefs.getAllRefs();
		for (Reference ref : refs) {
			RefList fromRefs = getFromRefs(ref.getFromAddress());
			fromRefs.removeRef(toAddr, ref.getOperandIndex());
			if (fromRefs.isEmpty()) {
				fromCache.delete(fromRefs.getKey());
			}
			referenceRemoved(ref);
		}
		toRefs.removeAll();
		toCache.delete(toRefs.getKey());
		return cnt;
	}
Remove all references that have the "To" address as
the given address.  NOTE: This method relies on the use of the ToRefs list!
Beyond version-12 of ProgramDB, Stack and Register addresses are no longer stored in the
ToRefs list.
@return number of references removed
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/references/ReferenceDBManager.java