when using fmt.Printf() many blanks are displayed

I'm trying to complete an echo server using golang.
server like this:

// use tcp to echo time
func main() {
	// listen tcp localhost:8000
	listener, err := net.Listen("tcp", "localhost:8000")
	if err != nil {
		fmt.Fprintf(os.Stderr, "listen error, %s", err)
		return
	}
	for {
		// accept
		connection, err := listener.Accept()
		if err != nil {
			fmt.Fprintf(os.Stderr, "listen error, %s\n", err)
		} else {
			handle(connection)
		}
	}
}

// handle the tcp connection
// return the time in one second gap
func handle(connection net.Conn) {
	defer connection.Close()
	for {
		// return written bytes, err
		if _, err := fmt.Fprintf(connection, time.Now().Format("15:04:05\n")); err != nil {
			// write error, probably the client close the connection
			fmt.Fprintf(os.Stderr, "%s close connection\n", connection.RemoteAddr())
			break
		}
		// wait one second
		time.Sleep(1 * time.Second)
	}
}

client like this

package main

const (
	proto = "tcp"
	addr  = "localhost:8000"
)

func main() {
	// client connect to tcp localhost:8000
	connection, err := net.Dial(proto, addr)
	if err != nil {
		fmt.Fprintf(os.Stderr, "connect to %s error, %s", addr, err)
	} else {
		buf := make([]byte, 1024)
		for {
			if _, err := connection.Read(buf); err != nil {
				fmt.Fprintf(os.Stderr, "read from %s error, %s\n", addr, err)
				break
			} else {
				fmt.Printf("data:%s ending\n", buf)
			}
		}
	}

}

When I run my code I get the following result:

I have no idea why so many blanks are shown.
I guess it's probably caused by the built-in function make, but why golang by default, displays so many blanks at the end of a string, unlike other high-level languages?
Could explain this and fix it?

Read returns n, the number of bytes read. Don't ignore it. Read into a buffer of length cap(buf): buf[:cap(buf)]. Then use n to update the buffer length: buf = buf[:n].

buf := make([]byte, 0, 1024)
for {
	n, err := connection.Read(buf[:cap(buf)])
	buf = buf[:n]
	if err != nil {
		fmt.Fprintf(os.Stderr, "read from %s error, %s\n", addr, err)
		break
	}
	fmt.Printf("data:%s ending\n", buf)
}

You are right, built-in make declare a slice with length and capacity equals to 1024.The better way to deal with such info is to use a protocol which can first read the size of the body, and declare the fit size of the reponse body.