Implement Reader in Go

reader.go

package main

import "golang.org/x/tour/reader"

type MyReader struct{}

func (MyReader) Read(b []byte) (n int, err error) {
	for i := 0; i < len(b); i ++ {
		b[i] = 'A'
	}
	return 1, nil
}

func main() {
	reader.Validate(MyReader{})
}