feat: implement Subscription type

gotrue/lib/types.py

@@ -1,6 +1,6 @@
 from dataclasses import dataclass
 from enum import Enum
-from typing import Any, Dict, Optional
+from typing import Any, Callable, Dict, Optional
 
 from gotrue.lib.helpers import parse_none
 
@@ -199,6 +199,19 @@ def to_dict(self) -> Dict[str, Any]:
         return data
 
 
+@dataclass
+class Subscription:
+    id: str
+    """The subscriber UUID. This will be set by the client."""
+    callback: Callable[["AuthChangeEvent", Optional[Session]], None]
+    """The function to call every time there is an event."""
+    unsubscribe: Callable[[], None]
+    """Call this to remove the listener."""
+
+    def __post_init__(self) -> None:
+        self.id = str(self.id)
+
+
 class AuthChangeEvent(str, Enum):
     SIGNED_IN = "SIGNED_IN"
     SIGNED_OUT = "SIGNED_OUT"