Use deque in ReplaySubject (#646)

Author: timothy-shields

reactivex/subject/replaysubject.py

@@ -1,6 +1,7 @@
 import sys
+from collections import deque
 from datetime import datetime, timedelta
-from typing import Any, List, NamedTuple, Optional, TypeVar, cast
+from typing import Any, Deque, NamedTuple, Optional, TypeVar, cast
 
 from reactivex.observer.scheduledobserver import ScheduledObserver
 from reactivex.scheduler import CurrentThreadScheduler
@@ -56,7 +57,7 @@ def __init__(
         self.window = (
             timedelta.max if window is None else self.scheduler.to_timedelta(window)
         )
-        self.queue: List[QueueItem] = []
+        self.queue: Deque[QueueItem] = deque()
 
     def _subscribe_core(
         self,
@@ -84,10 +85,10 @@ def _subscribe_core(
 
     def _trim(self, now: datetime) -> None:
         while len(self.queue) > self.buffer_size:
-            self.queue.pop(0)
+            self.queue.popleft()
 
         while self.queue and (now - self.queue[0].interval) > self.window:
-            self.queue.pop(0)
+            self.queue.popleft()
 
     def _on_next_core(self, value: _T) -> None:
         """Notifies all subscribed observers with the value."""