disable buffering for incremental statefile updates

src/capport/database.py

@@ -236,7 +236,7 @@ class Database:
 
         try:
             while True:
-                async with await trio.open_file(filename, 'ab') as sf:
+                async with await trio.open_file(filename, 'ab', buffering=0) as sf:
                     while True:
                         update = await rx.receive()
                         if isinstance(update, list):