More modern orthography
Turn off the network, add a key to alice’s map, then turn the network back on. Finally, make a change to bob’s map. Since alice sees that the incoming state from bob is missing that key, she removes it from her own state — even though bob never knew about that key in the first place. Whoops!
。PDF资料对此有专业解读
Crawler -- Storage : uses
当时就有人解释道，元宝早就接入微信了，但是需要在添加好友那里主动搜索元宝，然后再添加元宝为好友，才能把元宝放进你的好友栏里。
and as a result of this specification, you will get a fast, reliably correct algorithm that finds them. for example, if you have a notebook full of passwords, which you want to strip out before sharing, you can write a few fragments of a regex that each describe a property of passwords (e.g., contains at least 8 characters .{8,}, at least one uppercase letter _*[A-Z]_*, at least one digit _*[0-9]_*, and at least one special symbol _*[!#$@%^*]_*). and you can toggle each one on and off to see how it affects the matches. this is a nice intuitive way to write regexes, since intersection preserves the meaning of the original patterns and simply combines them, it works exactly as you would expect!