Exercise 3: Correcting "Leaks Cannot Detect Retain Cycles" — Possible Solution
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TASK
Rewrite "Leaks cannot detect retain cycles" so it is accurate according to
this chapter's sources, and say what you would still want to test.

REWRITE
"The Leaks instrument detects some retain cycles, which appear under Cycles
& Roots. It works by root analysis, so a cycle that nothing live references
can be reported. It may miss a cycle that a live object still references, so
a rising Persistent Bytes in Allocations is a useful second check."

WHAT I WOULD STILL TEST
- Build a small app with a deliberate cycle that nothing else references,
  profile it, and confirm Leaks reports it.
- Build a second version where a live object (for example a timer) also
  holds the cycle, and see whether Leaks reports it and whether
  Allocations shows the growth.

CAUTION
These findings come from search results and tutorials. I have not run the
test myself, and iOS Development - Architecture & Data 7 has not yet been
updated to match.