title: Private class in a struct
body: <p>I'm new to Go and couldn’t find a good solution for my problem.
  I have 2 types, the first one is private, because I want the programmer to use a constructor. The 2nd type has the first one inside it.</p>
  
  <p><a href="https://i.stack.imgur.com/BRBGi.png" rel="nofollow noreferrer">screenshot of foo bar example</a></p>
  
  <p>Sorry, I am not only new on GO, but also on stackoverflow question asking...so that’s why no code, but a screenshot</p>