protected void doAddXRef(DBTraceReferenceEntry entry) {
		if (!entry.toAddress.isMemoryAddress()) {
			return;
		}
		DBTraceReferenceSpace space = getReferenceSpace(entry.toAddress.getAddressSpace(), true);
		space.doAddXRef(entry);
	}
Ensures that a "from" address is in memory

<p>
NOTE: To manage references from registers, you must use
{@link #getReferenceRegisterSpace(TraceThread, boolean)}, which requires a thread.

@param space the space of the address to check
Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/database/symbol/DBTraceReferenceManager.java