Concurrent rpc balances queries

cmd/client/wallet/main.go

@@ -797,10 +797,17 @@ func FetchBalance(address common.Address) []*AccountState {
 
 			result[uint32(shardID)] = &AccountState{balance, 0}
 
-		LOOP:
+			var wgShard sync.WaitGroup
-			for j := 0; j < len(walletProfile.RPCServer[shardID]); j++ {
+			wgShard.Add(len(walletProfile.RPCServer[shardID]))
+
+			var mutexAccountState = &sync.Mutex{}
+
+			for rpcServerID := 0; rpcServerID < len(walletProfile.RPCServer[shardID]); rpcServerID++ {
+				go func(rpcServerID int) {
+					defer wgShard.Done()
+					log.Debug("Launched goroutiune");
 					for retry := 0; retry < rpcRetry; retry++ {
-					server := walletProfile.RPCServer[shardID][j]
+						server := walletProfile.RPCServer[shardID][rpcServerID]
 						client, err := clientService.NewClient(server.IP, server.Port)
 						if err != nil {
 							continue
@@ -816,13 +823,17 @@ func FetchBalance(address common.Address) []*AccountState {
 						log.Debug("FetchBalance", "response", response)
 						respBalance := big.NewInt(0)
 						respBalance.SetBytes(response.Balance)
+						mutexAccountState.Lock()
 						if balance.Cmp(respBalance) < 0 {
 							balance.SetBytes(response.Balance)
 							nonce = response.Nonce
 						}
-					break LOOP
+						mutexAccountState.Unlock()
 					}
+				}(rpcServerID)
 			}
+			wgShard.Wait()
+
 			result[shardID] = &AccountState{balance, nonce}
 		}(shardID)
 	}