@Override
	public long getEndSnap() {
		return snap;
	}
Construct an undefined unit

@param trace the trace
@param snap the snap
@param address the address
@param thread the thread, if in a per-thread space
@param frameLevel the frame, if in a per-frame space
Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/database/listing/UndefinedDBTraceData.java