feat: auto fit tensors across devices to guarantee optimal load (#1736)

examples/common/common.h

@@ -152,6 +152,7 @@ struct SDContextParams {
     std::string backend;
     std::string params_backend;
     std::string split_mode;
+    bool auto_fit = false;
     std::string rpc_servers;
     std::string effective_backend;
     std::string effective_params_backend;