private void findNext() {
		while (nextData == null && it.hasNext()) {
			CodeUnit cu = it.next();
			if (cu instanceof Data) {
				nextData = (Data) cu;
			}
		}
	}
@see ghidra.program.model.listing.DataIterator#next()
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/code/DataFilteredCodeUnitIterator.java