public long getLastThreadKey() {
		if (steps.isEmpty()) {
			return -1;
		}
		return steps.get(steps.size() - 1).getThreadKey();
	}
Get the key of the last thread stepped

@return the key, or -1 if no step in the sequence specifies a thread
Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/model/time/schedule/Sequence.java