public void flowStart(Address toAddr) {
		currentAddress = toAddr;
		
		if (trackStartEndState) {
			addrStartState.put(toAddr,new TraceDepthState(regVals.size(),regVals));
			regVals.push(new HashMap<Address, Varnode>());
		}
	}
Start flow at an address, recording any initial state for the current instruction
Ghidra/Features/Base/src/main/java/ghidra/program/util/VarnodeContext.java