From 8107a0ea2b54b591bd43e53cc02488d9676ea648 Mon Sep 17 00:00:00 2001
From: Igor Petruk <ipetruk@google.com>
Date: Mon, 23 Jan 2023 10:56:32 +0000
Subject: [PATCH] Update scoped-threads.md (#253)

Adding speaker notes explaining why scoped threads work and what borrowing rules apply.
---
 src/concurrency/scoped-threads.md | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/concurrency/scoped-threads.md b/src/concurrency/scoped-threads.md
index ba8f1960..1f58a828 100644
--- a/src/concurrency/scoped-threads.md
+++ b/src/concurrency/scoped-threads.md
@@ -31,3 +31,10 @@ fn main() {
 ```
 
 [1]: https://doc.rust-lang.org/std/thread/fn.scope.html
+
+<details>
+    
+* The reason for that is that when the `thread::scope` function completes, all the threads are guaranteed to be joined, so they can return borrowed data.
+* Normal Rust borrowing rules apply: you can either borrow mutably by one thread, or immutably by any number of threads.
+    
+</details>