Fixed crasing on limited number of requests

benchmark2.py

@@ -198,7 +198,8 @@ def run_benchmark(
                     worker.terminate()  # Not the nicest solution
 
     # Stop the input generator
-    input_generator_thread.active = False
+    if input_generator_thread:
+        input_generator_thread.active = False
 
     # read out all send requests to an array for handling later:
     results = {}