public VTMatchTag getMatchTag(long key) {
		lock.acquire();
		try {
			VTMatchTagDB matchTagDB = tagCache.get(key);
			if (matchTagDB != null) {
				return matchTagDB;
			}
			DBRecord record = matchTagAdapter.getRecord(key);
			if (record != null) {
				return new VTMatchTagDB(this, tagCache, record);
			}
		}
		catch (IOException e) {
			dbError(e);
		}
		finally {
			lock.release();
		}
		return VTMatchTag.UNTAGGED;
	}
Mark the state of a Version Tracking item as having changed and generate
the event of the specified type.  Any or all parameters may be null.
@param eventType event type
@param affected the version tracking object that was affected by the change.
@param oldValue original value or an Object that is related to the event.
@param newValue new value or an Object that is related to the event.
Ghidra/Features/VersionTracking/src/main/java/ghidra/feature/vt/api/db/VTSessionDB.java