public synchronized Set<T> getAllIndependentValues() {
		Set<T> set = createNodeSet();
		for (DependencyNode node : nodeMap.values()) {
			if (node.numberOfNodesThatIDependOn == 0) {
				set.add(node.value);
			}
		}
		return set;
	}
Returns the set of all values that have no dependencies regardless of whether or not
they have been "visited" (by the getUnvisitedIndependentValues() method.
@return return the set of all values that have no dependencies.
Ghidra/Framework/Generic/src/main/java/ghidra/util/graph/AbstractDependencyGraph.java