[Feat] Add native Mooncake KV transfer from AR to DiT (#7166)

Signed-off-by: asukaqaq-s <1311722138@qq.com>
Signed-off-by: Acerak01-fy <wfy2003324@163.com>
Co-authored-by: Acerak01-fy <wfy2003324@163.com>
Co-authored-by: amy-why-3459 <wuhaiyan17@huawei.com>

tests/diffusion/test_multiproc_engine_concurrency.py

@@ -835,11 +835,18 @@ class TestWorkerProcRpcRankStatus:
 
     def test_execute_rpc_returns_rank_status_envelope(self, monkeypatch):
         proc = self._make_worker_proc()
+        cpu_group = object()
 
         monkeypatch.setattr(torch.distributed, "is_initialized", lambda: True)
         monkeypatch.setattr(torch.distributed, "get_world_size", lambda: 2)
+        monkeypatch.setattr(
+            diffusion_worker_module,
+            "get_world_group",
+            lambda: SimpleNamespace(cpu_group=cpu_group),
+        )
 
-        def _all_gather_object(out, local):
+        def _all_gather_object(out, local, *, group):
+            assert group is cpu_group
             out[0] = local
             out[1] = {
                 "rank": 1,