diff --git a/hexlib/concurrency.py b/hexlib/concurrency.py
index 864703a..37c01f8 100644
--- a/hexlib/concurrency.py
+++ b/hexlib/concurrency.py
@@ -13,15 +13,18 @@ class StatefulStreamWorker:
 
     def run(self, q: Queue):
         for chunk in queue_iter(q, joinable=False, timeout=3):
-            self.process_chunk(chunk)
+            self._process_chunk(chunk)
 
-    def process_chunk(self, chunk):
+    def _process_chunk(self, chunk):
         for item in chunk:
             self.process(item)
 
     def process(self, item) -> None:
         raise NotImplementedError
 
+    def results(self):
+        raise NotImplementedError
+
 
 class StatefulStreamProcessor:
     def __init__(self, worker_factory, chunk_size=128, processes=1):
diff --git a/setup.py b/setup.py
index 40855f4..bc7bffc 100644
--- a/setup.py
+++ b/setup.py
@@ -2,7 +2,7 @@ from setuptools import setup
 
 setup(
     name="hexlib",
-    version="1.54",
+    version="1.55",
     description="Misc utility methods",
     author="simon987",
     author_email="me@simon987.net",