[PATCH 04/14] python: drop 'wait_closed' back compat helper

["Daniel P. Berrangé" <berrange@redhat.com>]

Our minimum python is now 3.9, so back compat with python
3.6 is no longer required.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 python/qemu/qmp/protocol.py |  3 +--
 python/qemu/qmp/util.py     | 29 -----------------------------
 2 files changed, 1 insertion(+), 31 deletions(-)

diff --git a/python/qemu/qmp/protocol.py b/python/qemu/qmp/protocol.py
index 9a7ada4a1e..deb6b20d29 100644
--- a/python/qemu/qmp/protocol.py
+++ b/python/qemu/qmp/protocol.py
@@ -41,7 +41,6 @@
     flush,
     pretty_traceback,
     upper_half,
-    wait_closed,
 )
 
 
@@ -830,7 +829,7 @@ async def _bh_close_stream(self, error_pathway: bool = False) -> None:
 
         self.logger.debug("Waiting for StreamWriter to close ...")
         try:
-            await wait_closed(self._writer)
+            await self._writer.wait_closed()
         except Exception:  # pylint: disable=broad-except
             # It's hard to tell if the Stream is already closed or
             # not. Even if one of the tasks has failed, it may have
diff --git a/python/qemu/qmp/util.py b/python/qemu/qmp/util.py
index 39fc341f2f..b5e9750576 100644
--- a/python/qemu/qmp/util.py
+++ b/python/qemu/qmp/util.py
@@ -104,35 +104,6 @@ def create_task(coro: Coroutine[Any, Any, T],
     return asyncio.ensure_future(coro, loop=loop)
 
 
-async def wait_closed(writer: asyncio.StreamWriter) -> None:
-    """
-    Python 3.6-compatible `asyncio.StreamWriter.wait_closed` wrapper.
-
-    :param writer: The `asyncio.StreamWriter` to wait on.
-    """
-    if sys.version_info >= (3, 7):
-        await writer.wait_closed()
-        return
-
-    # Python 3.6
-    transport = writer.transport
-    assert isinstance(transport, asyncio.WriteTransport)
-
-    while not transport.is_closing():
-        await asyncio.sleep(0)
-
-    # This is an ugly workaround, but it's the best I can come up with.
-    sock = transport.get_extra_info('socket')
-
-    if sock is None:
-        # Our transport doesn't have a socket? ...
-        # Nothing we can reasonably do.
-        return
-
-    while sock.fileno() != -1:
-        await asyncio.sleep(0)
-
-
 def asyncio_run(coro: Coroutine[Any, Any, T], *, debug: bool = False) -> T:
     """
     Python 3.6-compatible `asyncio.run` wrapper.
-- 
2.49.0