Fade graph no longer lagging

app/trackmanager.py

@@ -289,11 +289,19 @@ class _Music:
 
         self._adjust_by_ms(ms)
 
-    def play(self, path: str, position: Optional[float]) -> None:
+    def play(
+        self,
+        path: str,
+        start_time: dt.datetime,
+        position: Optional[float] = None,
+    ) -> None:
         """
         Start playing the track at path.
 
         Log and return if path not found.
+
+        start_time ensures our version and our caller's version of
+        the start time is the same
         """
 
         log.info(f"Music[{self.name}].play({path=}, {position=}")
@@ -310,7 +318,7 @@ class _Music:
 
             if position:
                 self.player.set_position(position)
-            self.start_dt = dt.datetime.now()
+            self.start_dt = start_time
 
             # For as-yet unknown reasons. sometimes the volume gets
             # reset to zero within 200mS or so of starting play. This
@@ -457,10 +465,11 @@ class _TrackManager:
     def play(self, position: Optional[float] = None) -> None:
         """Play track"""
 
-        self.player.play(self.path, position)
-
         now = dt.datetime.now()
         self.start_time = now
+
+        self.player.play(self.path, start_time=now, position=position)
+
         self.end_time = self.start_time + dt.timedelta(milliseconds=self.duration)
 
         # Calculate time fade_graph should start updating