private void symbolAdded(ProgramChangeRecord rec) {
		// NOTE: DOCR_SYMBOL_ADDED events are never generated for reference-based 
		// dynamic label symbols.  Reference events must be used to check for existence 
		// of a dynamic label symbol.
		Symbol symbol = (Symbol) rec.getNewValue();
		domainObjectWorker.schedule(new SymbolAddedJob(currentProgram, symbol));
	}
Tells a plugin that it is no longer needed.
The plugin should remove itself from anything that
it is registered to and release any resources.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/symtable/SymbolTablePlugin.java