Add SubscriptionAPI

And `TrioSubscriptionAPI`, to make subscription io-agnostic.

libp2p/tools/pubsub/dummy_account_node.py

@@ -61,7 +61,7 @@ class DummyAccountNode(Service):
     async def handle_incoming_msgs(self) -> None:
         """Handle all incoming messages on the CRYPTO_TOPIC from peers."""
         while True:
-            incoming = await self.subscription.receive()
+            incoming = await self.subscription.get()
             msg_comps = incoming.data.decode("utf-8").split(",")
 
             if msg_comps[0] == "send":

libp2p/tools/pubsub/floodsub_integration_test_settings.py

@@ -250,7 +250,7 @@ async def perform_test_from_obj(obj, pubsub_factory) -> None:
             # Look at each node in each topic
             for node_id in topic_map[topic]:
                 # Get message from subscription queue
-                msg = await queues_map[node_id][topic].receive()
+                msg = await queues_map[node_id][topic].get()
                 assert data == msg.data
                 # Check the message origin
                 assert node_map[origin_node_id].get_id().to_bytes() == msg.from_id