Add set_playback_rate method (#660)

* Add set_playback_rate method

* Update media.py

* Update media.py

---------

Co-authored-by: Erik Montnemery <[email protected]>

pychromecast/controllers/media.py

@@ -41,6 +41,7 @@
 TYPE_QUEUE_PREV = "QUEUE_PREV"
 TYPE_QUEUE_UPDATE = "QUEUE_UPDATE"
 TYPE_SEEK = "SEEK"
+TYPE_SET_PLAYBACK_RATE = "SET_PLAYBACK_RATE"
 TYPE_STOP = "STOP"
 
 METADATA_TYPE_GENERIC = 0
@@ -151,7 +152,8 @@ def adjusted_current_time(self) -> float | None:
             # Add time since last update
             return (
                 self.current_time
-                + (datetime.utcnow() - self.last_updated).total_seconds()
+                + self.playback_rate
+                * (datetime.utcnow() - self.last_updated).total_seconds()
             )
         # Not playing, return last reported seek time
         return self.current_time
@@ -660,6 +662,18 @@ def seek(self, position: float, timeout: float = 10.0) -> None:
         )
         response_handler.wait_response()
 
+    def set_playback_rate(self, playback_rate: float, timeout: float = 10.0) -> None:
+        """Set the playback rate. 1.0 is regular time, 0.5 is slow motion."""
+        response_handler = WaitResponse(timeout, "set playback rate")
+        self._send_command(
+            {
+                MESSAGE_TYPE: TYPE_SET_PLAYBACK_RATE,
+                "playbackRate": playback_rate,
+            },
+            response_handler.callback,
+        )
+        response_handler.wait_response()
+
     def queue_next(self, timeout: float = 10.0) -> None:
         """Send the QUEUE_NEXT command."""
         response_handler = WaitResponse(timeout, "queue next")