migrate paho.mqtt CallbackAPIVersion to VERSION2 (#225)

ha_addons/ha_addon/rootfs/home/proxy/protocol_ifc.py

@@ -0,0 +1,17 @@
+from abc import abstractmethod
+
+from async_ifc import AsyncIfc
+from iter_registry import AbstractIterMeta
+
+
+class ProtocolIfc(metaclass=AbstractIterMeta):
+    _registry = []
+
+    @abstractmethod
+    def __init__(self, addr, ifc: "AsyncIfc", server_side: bool,
+                 client_mode: bool = False, id_str=b''):
+        pass  # pragma: no cover
+
+    @abstractmethod
+    def close(self):
+        pass  # pragma: no cover