[1/N] DP-Refactor: move communicators into tokenizer_communicator_mixin (#10028)

python/sglang/utils.py

@@ -473,6 +473,10 @@ class TypeBasedDispatcher:
     def __init__(self, mapping: List[Tuple[Type, Callable]]):
         self._mapping = mapping
 
+    def __iadd__(self, other: "TypeBasedDispatcher"):
+        self._mapping.extend(other._mapping)
+        return self
+
     def __call__(self, obj: Any):
         for ty, fn in self._mapping:
             if isinstance(obj, ty):