feat(exapmles): add add_task_sanic.py

examples/add_task_sanic.py

@@ -0,0 +1,17 @@
+# -*- coding: utf-8 -*-
+
+import asyncio
+
+from sanic import Sanic
+
+app = Sanic()
+
+
+async def notify_server_started_after_five_seconds():
+    await asyncio.sleep(5)
+    print('Server successfully started!')
+
+app.add_task(notify_server_started_after_five_seconds())
+
+if __name__ == "__main__":
+    app.run(host="0.0.0.0", port=8000)