Fix type stubs for SymmetricMemory (#146310)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/146310
Approved by: https://github.com/yifuwang

torch/_C/_distributed_c10d.pyi

@@ -689,17 +689,48 @@ class _SymmetricMemory:
         dtype: torch.dtype,
         storage_offset: int | None = 0,
     ) -> torch.Tensor: ...
-    def barrier(self, channel: int = 0) -> None: ...
-    def put_signal(self, dst_rank: int, channel: int = 0) -> None: ...
-    def wait_signal(self, src_rank: int, channel: int = 0) -> None: ...
+    def get_signal_pad(
+        self,
+        rank: int,
+        sizes: torch.types._size = [],
+        dtype: torch.dtype | None = None,
+        storage_offset: int | None = 0,
+    ) -> torch.Tensor: ...
+    def barrier(self, channel: int = 0, timeout_ms: int = 0) -> None: ...
+    def put_signal(
+        self,
+        dst_rank: int,
+        channel: int = 0,
+        timeout_ms: int = 0,
+    ) -> None: ...
+    def wait_signal(
+        self,
+        src_rank: int,
+        channel: int = 0,
+        timeout_ms: int = 0,
+    ) -> None: ...
     @staticmethod
     def memset32(
-        tensor: torch.Tensor, offset: int, val: int, count: int
+        tensor: torch.Tensor, offset: int, val: int, count: int = 1
     ) -> torch.Tensor: ...
     @staticmethod
     def stream_write_value32(
         tensor: torch.Tensor, offset: int, val: int
     ) -> torch.Tensor: ...
+    @property
+    def buffer_ptrs(self) -> list[int]: ...
+    @property
+    def buffer_ptrs_dev(self) -> int: ...
+    @property
+    def signal_pad_ptrs(self) -> list[int]: ...
+    @property
+    def signal_pad_ptrs_dev(self) -> int: ...
+    @property
+    def multicast_ptr(self) -> int: ...
+    @property
+    def buffer_size(self) -> int: ...
+    @property
+    def signal_pad_size(self) -> int: ...
 
 class ProcessGroupXCCL(Backend):
     def __init__(