demos enhanced during workshop at Garoa

concurrency/timer_clo.py

@@ -0,0 +1,29 @@
+import sys
+import asyncio
+
+def make_show_remaining(seconds):
+    remaining = seconds
+
+    def show_remaining(loop):
+        nonlocal remaining
+        print('Remaining: ', remaining)
+        remaining -= 1
+        if remaining:
+            loop.call_later(1, show_remaining, loop)
+        else:
+            loop.stop()
+
+    return show_remaining
+    
+    
+def main(seconds=5):
+    seconds = int(seconds)
+    loop = asyncio.get_event_loop()
+    try:
+        loop.call_soon(make_show_remaining(seconds), loop)
+        loop.run_forever()
+    finally:
+        loop.close()
+
+if __name__ == '__main__':
+    main(*sys.argv[1:])