diff --git a/ptvp35/__init__.py b/ptvp35/__init__.py
index 4efb0a1..e9aba02 100644
--- a/ptvp35/__init__.py
+++ b/ptvp35/__init__.py
@@ -8,10 +8,10 @@ from typing import Any, Optional, IO, Type
 
 class Request:
     def set_result(self, result):
-        pass
+        raise NotImplementedError
 
     def set_exception(self, exception):
-        pass
+        raise NotImplementedError
 
 
 class KVRequest(Request):
@@ -38,7 +38,14 @@ class KVRequest(Request):
 
 
 class DumpRequest(Request):
-    pass
+    def __init__(self, future: Optional[asyncio.Future]):
+        self.future = future
+
+    def set_result(self, result):
+        self.future and self.future.set_result(result)
+
+    def set_exception(self, exception):
+        self.future and self.future.set_exception(exception)
 
 
 class UnkownRequestType(TypeError):
@@ -105,15 +112,16 @@ class Db:
         self.__mmdb[key] = value
         self.__queue.put_nowait(self.kvrequest_type(key, value, None))
 
-    async def _dump_buffer_or_request_so(self):
+    async def _dump_buffer_or_request_so(self, request: KVRequest):
         if self.__buffer.tell() >= self.buffersize:
             await self._dump_buffer()
+            request.set_result(None)
         else:
-            await self.__queue.put(DumpRequest())
+            await self.__queue.put(DumpRequest(request.future))
 
-    async def _write(self, line: str):
+    async def _write(self, line: str, request: KVRequest):
         self.__buffer.write(line)
-        await self._dump_buffer_or_request_so()
+        await self._dump_buffer_or_request_so(request)
 
     def _clear_buffer(self):
         self.__buffer = StringIO()
@@ -145,12 +153,12 @@ class Db:
 
     async def _handle_request(self, request: Request):
         if isinstance(request, self.kvrequest_type):
-            await self._write(request.line())
+            await self._write(request.line(), request)
         elif isinstance(request, DumpRequest):
             await self._dump_buffer()
+            request.set_result(None)
         else:
             raise UnkownRequestType
-        request.set_result(None)
 
     async def _background_cycle(self):
         request: Request = await self.__queue.get()