The Big Nerd Ranch Swift - End of chapter 24

Summary

• Memory Management and ARC
• Strong Reference Cycles
• Breaking Reference Cycles with weak
• Reference Cycles in Closures
• Excaping and Non-excaping Clousres
• For the More Curious : Can I Rretrieve the Reference Count of an Instance?

source code

It’s shame there’s no unowned reference. It would be in 3rd edition I think. The amazon says it will be released on May 6, 2019. I am happy with that. link