Don't compute time_to_sleep 2 times. (#51)

If jitter is configured it will produce randomness . This was done properly in sleep() so I can only assume this was an oversight.

Author: jdkessinger

httpx_retries/retry.py

@@ -238,7 +238,7 @@ async def asleep(self, response: Union[httpx.Response, Exception]) -> None:
         """
         time_to_sleep = self._calculate_sleep(response.headers if isinstance(response, httpx.Response) else {})
         logger.debug("asleep seconds=%s", time_to_sleep)
-        await asyncio.sleep(self._calculate_sleep(response.headers if isinstance(response, httpx.Response) else {}))
+        await asyncio.sleep(time_to_sleep)
 
     def increment(self) -> "Retry":
         """Return a new Retry instance with the attempt count incremented."""