[tasks] Add support for explicit time parameter

discord/utils.py

@@ -503,6 +503,13 @@ async def sane_wait_for(futures, *, timeout):
     return done
 
 
+def compute_timedelta(dt: datetime.datetime):
+    if dt.tzinfo is None:
+        dt = dt.astimezone()
+    now = datetime.datetime.now(datetime.timezone.utc)
+    return max((dt - now).total_seconds(), 0)
+
+
 async def sleep_until(when: datetime.datetime, result: Optional[T] = None) -> Optional[T]:
     """|coro|
 
@@ -520,11 +527,8 @@ async def sleep_until(when: datetime.datetime, result: Optional[T] = None) -> Op
     result: Any
         If provided is returned to the caller when the coroutine completes.
     """
-    if when.tzinfo is None:
-        when = when.astimezone()
-    now = datetime.datetime.now(datetime.timezone.utc)
-    delta = (when - now).total_seconds()
-    return await asyncio.sleep(max(delta, 0), result)
+    delta = compute_timedelta(when)
+    return await asyncio.sleep(delta, result)
 
 
 def utcnow() -> datetime.datetime: