Reduce Confusion

Hi

Thx for this awesome tute. As a noob, i appreciate the introduction. Suggestion: in the section on callbacks, you repeatedly go back and forth between blocking and non-blocking. To me, this is very confusing. I'd find it easier to understand if you separated your statements about blocking from your statements about non-blocking, like this:

In the blocking version a and b are both called/invoked (they both have () after them which executes the functions immediately). In the blocking version, there is no explicit relationship between a and b.

In the non-blocking version b is a callback to a. In the non-blocking version you will notice that only a gets invoked, and b is simply passed in to a as an argument. In the non-blocking version it becomes a's job to do what it needs to do and then call b when it is done.

Apri la sezione sui callback del tutorial e confronta le spiegazioni sui callback bloccanti e non bloccanti con la separazione suggerita in questa issue. Rivedi la sezione in modo che i due casi siano trattati separatamente, quindi verifica che la relazione tra i callback e il comportamento di invocazione rimangano chiari.