什么类型的异常可能会抛出String（contentsOf url：URL）？

I'm in that stage where I'm refactoring a prototype to be more flexible. Which means I want to add in error handling. My app relies pretty heavily on String(contentsOf:url) which, as with any action that deals with files, is error-prone. However the signature for the init method in question simply reads:I'm in that stage where I'm refactoring a proto