feat: add extension field to HeartbeatRequest (#4688)

* feat: add extension field to HeartbeatRequest

* chore: extension to extensions

* chore: upgrade proto

src/datanode/src/heartbeat.rs

@@ -324,10 +324,12 @@ impl HeartbeatTask {
                 region_id: stat.region_id.as_u64(),
                 engine: stat.engine,
                 role: RegionRole::from(stat.role).into(),
-                // TODO(jeremy): w/rcus
+                // TODO(weny): w/rcus
                 rcus: 0,
                 wcus: 0,
                 approximate_bytes: region_server.region_disk_usage(stat.region_id).unwrap_or(0),
+                // TODO(weny): add extensions
+                extensions: Default::default(),
             })
             .collect()
     }

src/datanode/src/region_server.rs

@@ -366,10 +366,10 @@ impl RegionServerHandler for RegionServer {
 
         // merge results by sum up affected rows and merge extensions.
         let mut affected_rows = 0;
-        let mut extension = HashMap::new();
+        let mut extensions = HashMap::new();
         for result in results {
             affected_rows += result.affected_rows;
-            extension.extend(result.extension);
+            extensions.extend(result.extensions);
         }
 
         Ok(RegionResponseV1 {
@@ -380,7 +380,7 @@ impl RegionServerHandler for RegionServer {
                 }),
             }),
             affected_rows: affected_rows as _,
-            extension,
+            extensions,
         })
     }
 }
@@ -708,7 +708,7 @@ impl RegionServerInner {
                     .await?;
                 Ok(RegionResponse {
                     affected_rows: result.affected_rows,
-                    extension: result.extension,
+                    extensions: result.extensions,
                 })
             }
             Err(err) => {