@Override
	public boolean hasReferences() {
		lock.acquire();
		try {
			checkIsValid();
			if (super.hasReferences()) {
				return true;
			}
			List<Long> thunkIds = functionMgr.getThunkFunctionIds(key);
			return thunkIds != null ? (thunkIds.size() != 0) : false;
		}
		finally {
			lock.release();
		}
	}
Construct a new FunctionSymbol
@param symbolMgr the symbol manager.
@param cache symbol object cache
@param address the address for this symbol.
@param record the record for this symbol.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/symbol/FunctionSymbol.java