Support loading weights from remote instance (#8215)

Signed-off-by: Anqi Shen <amy.saq@antgroup.com>
Co-authored-by: Chayenne <74843776+zhaochenyang20@users.noreply.github.com>

python/sglang/srt/managers/io_struct.py

@@ -1020,6 +1020,44 @@ class UpdateWeightsFromTensorReqOutput:
     message: str
 
 
+@dataclass
+class InitWeightsSendGroupForRemoteInstanceReqInput:
+    # The master address
+    master_address: str
+    # The ports for each rank's communication group
+    ports: str
+    # The rank in the communication group
+    group_rank: int
+    # The world size
+    world_size: int
+    # The group name
+    group_name: str = "weight_send_group"
+    # The backend
+    backend: str = "nccl"
+
+
+@dataclass
+class InitWeightsSendGroupForRemoteInstanceReqOutput:
+    success: bool
+    message: str
+
+
+@dataclass
+class SendWeightsToRemoteInstanceReqInput:
+    # The master address
+    master_address: str
+    # The ports for each rank's communication group
+    ports: str
+    # The group name
+    group_name: str = "weight_send_group"
+
+
+@dataclass
+class SendWeightsToRemoteInstanceReqOutput:
+    success: bool
+    message: str
+
+
 @dataclass
 class InitWeightsUpdateGroupReqInput:
     # The master address