Fix stale region cache with no leader

Signed-off-by: yongman <[email protected]>

src/region_cache.rs

@@ -85,7 +85,8 @@ impl<C: RetryClientTrait> RegionCache<C> {
                 .get(&candidate_region_ver_id)
                 .unwrap();
 
-            if region.contains(key) {
+            // Region in cache maybe stale if the region has not been elected leader yet during start.
+            if region.contains(key) && region.leader.is_some() {
                 return Ok(region.clone());
             }
         }
@@ -102,7 +103,11 @@ impl<C: RetryClientTrait> RegionCache<C> {
             let ver_id = region_cache_guard.id_to_ver_id.get(&id);
             if let Some(ver_id) = ver_id {
                 let region = region_cache_guard.ver_id_to_region.get(ver_id).unwrap();
-                return Ok(region.clone());
+
+                // Region in cache maybe stale if the region has not been elected leader yet during start.
+                if region.leader.is_some() {
+                    return Ok(region.clone());
+                }
             }
 
             // check concurrent requests