From 1c764068b9b2d0844fc16224b257f84bc06c86e9 Mon Sep 17 00:00:00 2001
From: Svyatoslav Nikolsky <svyatonik@gmail.com>
Date: Thu, 16 May 2024 14:57:15 +0300
Subject: [PATCH] added code comment

---
 bridges/relays/client-substrate/src/client.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/bridges/relays/client-substrate/src/client.rs b/bridges/relays/client-substrate/src/client.rs
index 8a9b5c767aff..2e7cb7455f76 100644
--- a/bridges/relays/client-substrate/src/client.rs
+++ b/bridges/relays/client-substrate/src/client.rs
@@ -79,6 +79,8 @@ pub fn is_ancient_block<N: From<u32> + PartialOrd + Saturating>(block: N, best:
 /// Opaque justifications subscription type.
 pub struct Subscription<T>(
 	pub(crate) Mutex<futures::channel::mpsc::Receiver<Option<T>>>,
+	// The following field is not explicitly used by the code. But when it is dropped,
+	// the bakground task receives a shutdown signal.
 	#[allow(dead_code)] pub(crate) futures::channel::oneshot::Sender<()>,
 );
 
@@ -856,6 +858,7 @@ impl<T: DeserializeOwned> Subscription<T> {
 			match item {
 				Some(item) => Some((item, Some(this))),
 				None => {
+					// let's make it explicit here
 					let _ = this.1.send(());
 					None
 				},