diff --git a/book/en/src/by-example/types-send-sync.md b/book/en/src/by-example/types-send-sync.md
index da53cf963f..8ec62e6569 100644
--- a/book/en/src/by-example/types-send-sync.md
+++ b/book/en/src/by-example/types-send-sync.md
@@ -39,6 +39,11 @@ The example below shows where a type that doesn't implement `Send` can be used.
 {{#include ../../../../examples/not-send.rs}}
 ```
 
+It's important to note that late initialization of resources is effectively a
+send operation where the initial value is sent from `idle`, which has the lowest
+priority of `0`, to a task with will run with a priority greater than or equal
+to `1`. Thus all late resources need to implement the `Send` trait.
+
 ## `Sync`
 
 Similarly, [`Sync`] is a marker trait for "types for which it is safe to share