why i send once, but receive twice

[skmygdrs]

server

package main

import (
	"fmt"
	"math/rand"
	"time"

	czmq "github.com/zeromq/goczmq"
)

func main() {
	pubEndpoint := "tcp://*:5556"
	pubSock, err := czmq.NewPub(pubEndpoint)
	if err != nil {
		panic(err)
	}

	defer pubSock.Destroy()
	pubSock.Bind(pubEndpoint)

	for {
		zipcode := rand.Intn(100000)
		temperature := rand.Intn(215) - 85
		relHumidity := rand.Intn(50) + 10

		msg := fmt.Sprintf("%d %d %d", zipcode, temperature, relHumidity)
		err := pubSock.SendFrame([]byte(msg), 0)
		if err != nil {
			panic(err)
		}
		fmt.Println("send", msg)
		time.Sleep(time.Second * 10)
	}
}

client

package main

import (
	"fmt"
	"strconv"
	"strings"

	czmq "github.com/zeromq/goczmq"
)

func main() {

	pubEndpoint := "tcp://127.0.0.1:5556"
	filter := ""

	subSock, err := czmq.NewSub(pubEndpoint, filter)
	if err != nil {
		panic(err)
	}

	defer subSock.Destroy()

	fmt.Printf("Collecting updates from weather server for %s…\n", filter)
	subSock.Connect(pubEndpoint)

	for i := 0; i < 100; i++ {
		msg, _, err := subSock.RecvFrame()
		if err != nil {
			panic(err)
		}
		fmt.Println("recv msg", i, string(msg))
		weatherData := strings.Split(string(msg), " ")
		temperature, err := strconv.ParseInt(weatherData[1], 10, 64)
		fmt.Println("recv temperature", temperature)
	}

}

server output

send 5384 2 27
send 86137 -34 54
send 97726 52 41
send 12079 46 30
send 30493 126 29
send 98981 67 35
send 44885 105 47
send 73749 88 28
send 4384 53 34
send 64547 92 42
send 3616 -11 50
send 25786 -14 36

client output

recv msg 0 54425 55 16
recv temperature 55
recv msg 1 54425 55 16
recv temperature 55
recv msg 2 3300 -31 21
recv temperature -31
recv msg 3 3300 -31 21
recv temperature -31
recv msg 4 28162 64 38
recv temperature 64
recv msg 5 28162 64 38
recv temperature 64

[skmygdrs]

server output
send 98081 -43 57
send 84059 -79 28
send 54425 55 16
send 3300 -31 21
send 28162 64 38
send 33274 106 55
send 23237 41 55
send 65466 48 18

client outpub
Collecting updates from weather server for …
recv msg 0 54425 55 16
recv temperature 55
recv msg 1 54425 55 16
recv temperature 55
recv msg 2 3300 -31 21
recv temperature -31
recv msg 3 3300 -31 21
recv temperature -31
recv msg 4 28162 64 38
recv temperature 64
recv msg 5 28162 64 38
recv temperature 64
recv msg 6 33274 106 55
recv temperature 106
recv msg 7 33274 106 55
recv temperature 106
recv msg 8 23237 41 55
recv temperature 41
recv msg 9 23237 41 55
recv temperature 41
recv msg 10 65466 48 18
recv temperature 48
recv msg 11 65466 48 18
recv temperature 48