Reader wrapper to have functional programming style of reading io (no mutables)

main.go

package main

import (
	"fmt"
	"io"
	"os"
)

func main() {
	f, err := os.Open("./temp")
	defer f.Close()
	check(err)

	res := Read(f, 5)
	fmt.Printf(string(res))

	res = Read(f, 5)
	fmt.Printf(string(res))

	res = Read(f, 5)
	fmt.Printf("%s\n", string(res))
}

// Reader wrapper to avoid mutable slice of byte
func Read(r io.Reader, size int) []byte {
	d := make([]byte, size)
	r.Read(d)
	return d
}

func check(e error) {
	if e != nil {
		panic(e)
	}
}