From 652f0ae7287794d7cd476d4965e143b2f3901bb4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=B6ren=20Meier?= <soeren@s-me.ch>
Date: Sat, 15 May 2021 11:56:24 +0200
Subject: [PATCH] sync: add receiver_count to watch::Sender (#3729)

---
 tokio/src/sync/watch.rs | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/tokio/src/sync/watch.rs b/tokio/src/sync/watch.rs
index db65e5a5e29..42d417a0fe5 100644
--- a/tokio/src/sync/watch.rs
+++ b/tokio/src/sync/watch.rs
@@ -417,6 +417,28 @@ impl<T> Sender<T> {
             Receiver::from_shared(version, shared)
         }
     }
+
+    /// Returns the number of receivers that currently exist
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use tokio::sync::watch;
+    ///
+    /// #[tokio::main]
+    /// async fn main() {
+    ///     let (tx, rx1) = watch::channel("hello");
+    ///
+    ///     assert_eq!(1, tx.receiver_count());
+    ///
+    ///     let mut _rx2 = rx1.clone();
+    ///
+    ///     assert_eq!(2, tx.receiver_count());
+    /// }
+    /// ```
+    pub fn receiver_count(&self) -> usize {
+        self.shared.ref_count_rx.load(Relaxed)
+    }
 }
 
 impl<T> Drop for Sender<T> {