fix prometheus on windows, maybe

src/_zkapauthorizer/_storage_server.py

@@ -65,6 +65,12 @@ try:
 except ImportError:
     pass
 
+# Hack around a bug in prometheus_client
+def _prometheus_client_fix():
+    import prometheus_client.exposition
+    prometheus_client.exposition.FileNotFoundError = IOError
+_prometheus_client_fix()
+
 # See allmydata/storage/mutable.py
 SLOT_HEADER_SIZE = 468
 LEASE_TRAILER_SIZE = 4