diff --git a/libp2p/pubsub/gossipsub.py b/libp2p/pubsub/gossipsub.py
index d09db76..ea2594e 100644
--- a/libp2p/pubsub/gossipsub.py
+++ b/libp2p/pubsub/gossipsub.py
@@ -106,7 +106,8 @@ class GossipSub(IPubsubRouter):
         logger.debug("attached to pusub")
 
         # Start heartbeat now that we have a pubsub instance
-        # TODO: Start after delay
+        # Start after a delay. Ref: https://github.com/libp2p/go-libp2p-pubsub/blob/01b9825fbee1848751d90a8469e3f5f43bac8466/gossipsub.go#L410  # Noqa: E501
+        await asyncio.sleep(0.1)
         asyncio.ensure_future(self.heartbeat())
 
     def add_peer(self, peer_id: ID, protocol_id: TProtocol) -> None:
@@ -127,8 +128,7 @@ class GossipSub(IPubsubRouter):
             #   instance in multistream-select, but it is not the protocol that gossipsub supports.
             #   In this case, probably we registered gossipsub to a wrong `protocol_id`
             #   in multistream-select, or wrong versions.
-            # TODO: Better handling
-            raise Exception(f"protocol is not supported: protocol_id={protocol_id}")
+            raise Exception(f"This should not happen. Protocol={protocol_id} is not supported.")
         self.peers_to_protocol[peer_id] = protocol_id
 
     def remove_peer(self, peer_id: ID) -> None:
@@ -187,7 +187,6 @@ class GossipSub(IPubsubRouter):
             stream = self.pubsub.peers[peer_id]
             # FIXME: We should add a `WriteMsg` similar to write delimited messages.
             #   Ref: https://github.com/libp2p/go-libp2p-pubsub/blob/master/comm.go#L107
-            # TODO: Go use `sendRPC`, which possibly piggybacks gossip/control messages.
             try:
                 await stream.write(encode_varint_prefixed(rpc_msg.SerializeToString()))
             except StreamClosed:
@@ -218,15 +217,9 @@ class GossipSub(IPubsubRouter):
 
             # gossipsub peers
             in_topic_gossipsub_peers: List[ID] = None
-            # TODO: Do we need to check `topic in self.pubsub.my_topics`?
             if topic in self.mesh:
                 in_topic_gossipsub_peers = self.mesh[topic]
             else:
-                # TODO(robzajac): Is topic DEFINITELY supposed to be in fanout if we are not
-                #   subscribed?
-                # I assume there could be short periods between heartbeats where topic may not
-                # be but we should check that this path gets hit appropriately
-
                 if (topic not in self.fanout) or (len(self.fanout[topic]) == 0):
                     # If no peers in fanout, choose some peers from gossipsub peers in topic.
                     self.fanout[topic] = self._get_in_topic_gossipsub_peers_from_minus(
@@ -373,7 +366,6 @@ class GossipSub(IPubsubRouter):
         for topic in self.mesh:
             msg_ids = self.mcache.window(topic)
             if msg_ids:
-                # TODO: Make more efficient, possibly using a generator?
                 # Get all pubsub peers in a topic and only add them if they are gossipsub peers too
                 if topic in self.pubsub.peer_topics:
                     # Select D peers from peers.gossipsub[topic]
@@ -397,7 +389,6 @@ class GossipSub(IPubsubRouter):
             if topic not in self.mesh:
                 msg_ids = self.mcache.window(topic)
                 if msg_ids:
-                    # TODO: Make more efficient, possibly using a generator?
                     # Get all pubsub peers in topic and only add if they are gossipsub peers also
                     if topic in self.pubsub.peer_topics:
                         # Select D peers from peers.gossipsub[topic]
@@ -409,7 +400,6 @@ class GossipSub(IPubsubRouter):
                                 peer not in self.mesh[topic]
                                 and peer not in self.fanout[topic]
                             ):
-
                                 msg_id_strs = [str(msg) for msg in msg_ids]
                                 await self.emit_ihave(topic, msg_id_strs, peer)