Drive circuit-breaker probes for validator notification streams with a timer

linera-core/src/client/mod.rs

@@ -761,14 +761,8 @@ impl<Env: Environment> Client<Env> {
         // Download remaining certificates from the remote node using a pipelined
         // sliding window. A background task downloads up to `max_concurrent_batch_downloads`
         // batches concurrently and sends them through a channel for sequential processing.
-        #[cfg(not(web))]
-        type CertificateBatchFuture = std::pin::Pin<
-            Box<dyn Future<Output = Result<Vec<ConfirmedBlockCertificate>, NodeError>> + Send>,
-        >;
-        #[cfg(web)]
-        type CertificateBatchFuture = std::pin::Pin<
-            Box<dyn Future<Output = Result<Vec<ConfirmedBlockCertificate>, NodeError>>>,
-        >;
+        type CertificateBatchFuture =
+            crate::MaybeSendBoxFuture<'static, Result<Vec<ConfirmedBlockCertificate>, NodeError>>;
 
         let max_concurrent = self.options.max_concurrent_batch_downloads;
         let batch_size = self.options.certificate_download_batch_size;

linera-core/src/lib.rs

@@ -29,6 +29,18 @@ mod local_node;
 pub mod node;
 /// Utilities for notifying subscribers about chain events.
 pub mod notifier;
+
+/// A boxed future that is `Send` on native targets and not on web, where there is a
+/// single thread. Keeps the `Send` policy for boxed futures in one place.
+#[cfg(not(web))]
+pub(crate) type MaybeSendBoxFuture<'a, T> =
+    std::pin::Pin<Box<dyn std::future::Future<Output = T> + Send + 'a>>;
+/// A boxed future that is `Send` on native targets and not on web, where there is a
+/// single thread. Keeps the `Send` policy for boxed futures in one place.
+#[cfg(web)]
+pub(crate) type MaybeSendBoxFuture<'a, T> =
+    std::pin::Pin<Box<dyn std::future::Future<Output = T> + 'a>>;
+
 pub mod proof;
 /// A validator node paired with the validator's public key.
 pub mod remote_node;