bufio的ReadLine是不是必须检测io.EOF

package main

import (
    "bufio"
    "fmt"
    "os"
)

func main() {

    filename := "go.sum"

    fi, err := os.Open(filename)
    if err != nil {
        panic(err)
    }
    defer fi.Close()

    buf := bufio.NewReader(fi)

    for {

        line, _, err := buf.ReadLine()
//if err == io.EOF { break }
        if err != nil {
            panic(err)
        }

        fmt.Println(string(line))

    }
}

panic: EOF

goroutine 1 [running]: main.main() ReadLine-EOF.go:28 +0x325 exit status 2