add async examples

Author: slxiao

python-async/async_example.py

@@ -0,0 +1,13 @@
+import time
+import asyncio
+
+async def hellworld(sleep_time):
+    print('hellworld starts, then sleep for %s seconds' % sleep_time)
+    await asyncio.sleep(sleep_time)
+    print('hellworld ends, after sleep: %s seconds' % sleep_time)
+
+loop = asyncio.get_event_loop()
+
+start = time.time()
+loop.run_until_complete(asyncio.gather(hellworld(1), hellworld(2)))
+print("Running program takes: %s seconds" % (time.time() - start))

python-async/sync_example.py

@@ -0,0 +1,11 @@
+import time
+
+def hellworld(sleep_time):
+    print('hellworld starts, then sleep for %s seconds' % sleep_time)
+    time.sleep(sleep_time)
+    print('hellworld ends, after sleep: %s seconds' % sleep_time)
+
+start = time.time()
+hellworld(1)
+hellworld(2)
+print("Running program takes: %s seconds" % (time.time() - start))