HAR-65: use better broadcast model for ping message

Signed-off-by: Leo Chen <leo@harmony.one>

node/node_handler.go

@@ -542,9 +542,7 @@ func (node *Node) pingMessageHandler(msgPayload []byte) int {
 	pong := proto_node.NewPongMessage(peers, node.Consensus.PublicKeys)
 	buffer := pong.ConstructPongMessage()
 
-	for _, p := range peers {
-		p2p.SendMessage(p, buffer)
-	}
+	p2p.BroadcastMessageFromLeader(peers, buffer)
 
 	return len(peers)
 }

p2p/peer.go

@@ -80,14 +80,12 @@ func BroadcastMessageFromLeader(peers []Peer, msg []byte) {
 	// TODO(minhdoan): Enable back for multicast.
 	peers = SelectMyPeers(peers, 1, MaxBroadCast)
 	BroadcastMessage(peers, msg)
-	log.Info("Done sending from leader")
 }
 
 // BroadcastMessageFromValidator sends the message to a list of peers from a validator.
 func BroadcastMessageFromValidator(selfPeer Peer, peers []Peer, msg []byte) {
 	peers = SelectMyPeers(peers, selfPeer.ValidatorID*MaxBroadCast+1, (selfPeer.ValidatorID+1)*MaxBroadCast)
 	BroadcastMessage(peers, msg)
-	log.Info("Done sending from validator")
 }
 
 // ConstructP2pMessage constructs the p2p message as [messageType, contentSize, content]