Fixed missing String value in Samples, see fc745f8

Author: smarek

sample/src/main/res/values/strings.xml

@@ -36,4 +36,5 @@
     <string name="title_range_sample">Range response handling</string>
     <string name="title_401_unauth">401 basic authentication</string>
     <string name="title_pre_post_processing">Pre-/Post-processing</string>
+    <string name="title_async_background_thread">Async on background thread</string>
 </resources>