refactor: Take the baseline flag value in AsyncFlagValueChangeListener init

Author: jsonbailey

ldclient/impl/async_flag_tracker.py

@@ -9,22 +9,21 @@
 class AsyncFlagValueChangeListener:
     """Calls the user's listener when a specific flag's evaluated value changes for a specific context."""
 
-    def __init__(self, key: str, context: Context, listener: Callable[[FlagValueChange], None], eval_fn: Callable, scheduler: AsyncCallbackScheduler):
+    def __init__(self, key: str, context: Context, listener: Callable[[FlagValueChange], None], eval_fn: Callable, scheduler: AsyncCallbackScheduler, value: Any):
         self.__key = key
         self.__context = context
         self.__listener = listener
         self.__eval_fn = eval_fn
         self.__scheduler = scheduler
 
         self.__lock = AsyncLock()
-        self.__value: Any = None
+        self.__value = value
 
     @classmethod
     async def create(cls, key: str, context: Context, listener: Callable[[FlagValueChange], None], eval_fn: Callable, scheduler: AsyncCallbackScheduler) -> 'AsyncFlagValueChangeListener':
         """Evaluates the flag once to capture the baseline value, then returns the listener."""
-        instance = cls(key, context, listener, eval_fn, scheduler)
-        instance.__value = await eval_fn(key, context)
-        return instance
+        value = await eval_fn(key, context)
+        return cls(key, context, listener, eval_fn, scheduler, value)
 
     def __call__(self, flag_change: FlagChange):
         self.__scheduler.call(self._on_flag_change, flag_change)