private void symbolPrimaryStateChanged(ProgramChangeRecord rec) {
		Symbol symbol = (Symbol) rec.getNewValue();
		Symbol oldPrimarySymbol = (Symbol) rec.getOldValue();
		domainObjectWorker
				.schedule(new SymbolSetAsPrimaryJob(currentProgram, symbol, oldPrimarySymbol));
	}
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