feat/bulk-wal:

 Enhance error handling and metrics in `bulk_insert.rs`

 - Updated `Inserter` to improve error handling by capturing the result of `datanode.handle(request)` and incrementing the `DIST_INGEST_ROW_COUNT` metric with the number of affected rows.

Author: v0y4g3r

src/operator/src/bulk_insert.rs

@@ -103,11 +103,15 @@ impl Inserter {
                 .with_label_values(&["datanode_handle"])
                 .start_timer();
             let datanode = self.node_manager.datanode(&datanode).await;
-            return datanode
+            let result = datanode
                 .handle(request)
                 .await
                 .context(error::RequestRegionSnafu)
                 .map(|r| r.affected_rows);
+            if let Ok(rows) = result {
+                crate::metrics::DIST_INGEST_ROW_COUNT.inc_by(rows as u64);
+            }
+            return result;
         }
 
         let mut mask_per_datanode = HashMap::with_capacity(region_masks.len());