PROTON-2890: [Python examples] Simple recv now deduplicates more accurately

This does use an ever expanding set, so this is not suitable for
production use! For production use maybe the ids in the deduplication
cache could be removed after a certain number of new messages have been
received.

Author: astitcher

python/examples/simple_recv.py

@@ -29,16 +29,20 @@ def __init__(self, url, count):
         self.url = url
         self.expected = count
         self.received = 0
+        self.dedup_ids = set()
 
     def on_start(self, event):
         event.container.create_receiver(self.url)
 
     def on_message(self, event):
-        if event.message.id and event.message.id < self.received:
+        message = event.message
+        if message.id in self.dedup_ids:
             # ignore duplicate message
+            print(f"duplicate message ignored {message.id}")
             return
+        self.dedup_ids.add(message.id)
         if self.expected == 0 or self.received < self.expected:
-            print(event.message.body)
+            print(f"{message}")
             self.received += 1
             if self.received == self.expected:
                 event.receiver.close()