diff --git a/aiosched/io.py b/aiosched/io.py
index d48c79e..92323eb 100644
--- a/aiosched/io.py
+++ b/aiosched/io.py
@@ -99,7 +99,6 @@ class AsyncStream:
         await io_release(self.stream)
         self.stream.close()
         self.stream = None
-        await aiosched.checkpoint()
 
     async def fileno(self):
         """
diff --git a/aiosched/task.py b/aiosched/task.py
index b669686..ee65683 100644
--- a/aiosched/task.py
+++ b/aiosched/task.py
@@ -142,5 +142,5 @@ class Task:
 
         if not self.done():
             warnings.warn(f"task '{self.name}' was destroyed, but it has not completed yet")
-        if self.last_io:
-            warnings.warn(f"task '{self.name}' was destroyed, but it has pending I/O")
+        if self.last_io and self.last_io[1].fileno() != -1:
+            warnings.warn(f"task '{self.name}' was destroyed, but it has pending I/O: forgot to close a resource?")