Fix the broadcast bug introduced by for loop deferencing to the last element (for loop variable is just a temp pointer to the element)

consensus/consensus.go

@@ -146,8 +146,8 @@ func NewConsensus(ip, port, ShardID string, peers []p2p.Peer, leader p2p.Peer) C
 
 	if consensus.IsLeader {
 		consensus.ReadySignal = make(chan int)
-		// TODO: why do we need to do go rountine here.
 		// send a signal to indicate it's ready to run consensus
+		// this is a goroutine because go channel without buffer will block
 		go func() {
 			consensus.ReadySignal <- 1
 		}()

p2p/peer.go

@@ -32,11 +32,12 @@ func BroadcastMessage(peers []Peer, msg []byte) {
 
 	var wg sync.WaitGroup
 	wg.Add(len(peers))
+
 	for _, peer := range peers {
-		// send(peer.Ip, peer.Port, content)
+		peerCopy := peer
 		go func() {
 			defer wg.Done()
-			send(peer.Ip, peer.Port, content)
+			send(peerCopy.Ip, peerCopy.Port, content)
 		}()
 	}
 	wg.Wait()