public T getBefore(long snap, Address address) {
		Address prev = prevAddress(address);
		if (prev == null) {
			return null;
		}
		return getFloor(snap, prev);
	}
@see TraceBaseCodeUnitsView#getBefore(long, Address)
@param snap the snap
@param address the address
@return the unit or null
Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/database/listing/AbstractBaseDBTraceCodeUnitsMemoryView.java