diff --git a/Lib/tempfile.py b/Lib/tempfile.py
index ae35314..0dbd889 100644
--- a/Lib/tempfile.py
+++ b/Lib/tempfile.py
@@ -175,11 +175,14 @@
             filename = _os.path.join(dir, name)
             try:
                 fd = _os.open(filename, _bin_openflags, 0o600)
-                fp = _io.open(fd, 'wb')
-                fp.write(b'blat')
-                fp.close()
-                _os.unlink(filename)
-                del fp, fd
+                try:
+                    try:
+                        fp = _io.open(fd, 'wb', buffering=0, closefd=False)
+                        fp.write(b'blat')
+                    finally:
+                        _os.close(fd)
+                finally:
+                    _os.unlink(filename)
                 return dir
             except (OSError, IOError) as e:
                 if e.args[0] != _errno.EEXIST: