[Fix on Mac] Data format (#848)

* Add serialization

* add serialization

* add serialization

* lalalalalalalala

* lalalalalalalala

* serialize

* serialize

* nnn

* WIP: import tvm runtime node system

* WIP: object system

* containers

* tested basic container composition

* tested custom object

* tmp

* fix setattr bug

* tested object container return

* fix lint

* some comments about get/set state

* fix lint

* fix lint

* update cython

* fix cython

* ffi doc

* fix doc

* WIP: using object system for graph

* c++ side refactoring done; compiled

* remove stale apis

* fix bug in DGLGraphCreate; passed test_graph.py

* fix bug in python modify; passed utest for pytorch/cpu

* fix lint

* Add serialization

* Add serialization

* fix

* fix typo

* serialize with new ffi

* commit

* commit

* commit

* save

* save

* save

* save

* commit

* clean

* Delete tt2.py

* fix lint

* Add serialization

* fix lint 2

* fix lint

* fix lint

* fix lint

* fix lint

* Fix Lint

* Add serialization

* Change to Macro

* fix

* fix

* fix bugs

* refactor

* refactor

* updating dmlc-core to include force flag

* trying tempfile

* delete leaked pointer

* Fix assert

* fix assert

* add comment and test case

* add graph labels

* add load labels

* lint

* lint

* add graph labels

* lint

*  fix windows

* fix

* update dmlc-core to latest

* fix

* fix camel naming

* fix

* poke ci

src/graph/graph_serialize.cc

@@ -99,7 +99,7 @@ DGL_REGISTER_GLOBAL("data.graph_serialize._CAPI_DGLLoadGraphs")
     std::string filename = args[0];
     List<Value> idxs = args[1];
     bool onlyMeta = args[2];
-    std::vector<size_t> idx_list(idxs.size());
+    std::vector<dgl_id_t> idx_list(idxs.size());
     for (uint64_t i = 0; i < idxs.size(); ++i) {
       idx_list[i] = static_cast<dgl_id_t >(idxs[i]->data);
     }