@Override
	public int getBytes(ByteBuffer buffer, int addressOffset) {
		DBTraceMemorySpace mem = trace.getMemoryManager().get(this, false);
		if (mem == null) {
			// TODO: 0-fill instead? Will need to check memory space bounds.
			return 0;
		}
		return mem.getBytes(getStartSnap(), address.add(addressOffset), buffer);
	}
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