Xcode recently reminded me of the content. I wonder if the "LRUCache" class is defined in "CFNetwork"?
Class LRUCache is implemented in both /System/Library/Frameworks/CFNetwork.framework/CFNetwork (0x1ef1b6428) and /private/var/containers/Bundle/Application/84DAC0CA-9561-4510-8050-CD6CD9F7D7E7/ckditu.app/ckditu (0x10503ce70). One of the two will be used. Which one is undefined.