fix: do not take write lock for maybe_network_lost() and set_push_device_token()

src/accounts.rs

@@ -344,7 +344,7 @@ impl Accounts {
     }
 
     /// Sets notification token for Apple Push Notification service.
-    pub async fn set_push_device_token(&mut self, token: &str) -> Result<()> {
+    pub async fn set_push_device_token(&self, token: &str) -> Result<()> {
         self.push_subscriber.set_device_token(token).await;
         Ok(())
     }

src/push.rs

@@ -31,7 +31,7 @@ impl PushSubscriber {
     }
 
     /// Sets device token for Apple Push Notification service.
-    pub(crate) async fn set_device_token(&mut self, token: &str) {
+    pub(crate) async fn set_device_token(&self, token: &str) {
         self.inner.write().await.device_token = Some(token.to_string());
     }