What's more, developers have to reason about each and every line in the code, looking to see if it needs to be protected because too much synchronization is just as bad as too little.
此外，开发人员需要对每一行代码刨根知底，以确定是否需要保护它们，因为过度同步与过少同步同样有害。
2
Subsequent invocations do not require synchronization because the first invocation is the only invocation that executes the code at //2, which is the only line that requires synchronization.
由于只有第一次调用执行了 //2 处的代码，而只有此行代码需要同步，因此就无需对后续调用使用同步。
3
The rsync utility is a mandatory tool for your command-line work, and you need to learn how to use it for easy, safe, quick laptop-desktop synchronization.