Go - Functions - 5 (variadic function, defer)

• Declare variadic function
• Variadic function parameter type is .... Different from slice.
  
• Action can be defered with a defer statement. Defered function will be called after function contains the defer statement has been done (after return value).
• Any number of defer can be declared, it will be executed by reversed defer order.
  
  
  
• Need extra parentheses when defer a function. Ex. defer f()()
  
• A defered function can observe the function’s result.
  
• A defered function can even change the result. Ex.