fatal error: all goroutines are asleep - deadlock!

gistfile1.txt

package main

import (
	"bufio"
	"fmt"
	"io"
)

func main() {
	r, w := io.Pipe()
	reader := bufio.NewReader(r)
	writer := bufio.NewWriter(w)

	fmt.Fprintln(writer, "hello world")
	reader.ReadLine()
}