Fix ASAN failure
diff --git a/src/cpp/server/server_context.cc b/src/cpp/server/server_context.cc
index 05c05c8..01e9c00 100644
--- a/src/cpp/server/server_context.cc
+++ b/src/cpp/server/server_context.cc
@@ -166,6 +166,10 @@
   call->PerformOps(completion_op_);
 }
 
+CompletionQueueTag* ServerContext::GetCompletionOpTag() {
+  return static_cast<CompletionQueueTag*>(completion_op_);
+}
+
 void ServerContext::AddInitialMetadata(const grpc::string& key,
                                        const grpc::string& value) {
   initial_metadata_.insert(std::make_pair(key, value));