Exercise: Readers

题目：

Implement a Reader type that emits an infinite stream of the ASCII character 'A'.
实现一个Reader 类型，只含有'A'的流。

代码：

package main

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

type MyReader struct{}

// TODO: Add a Read([]byte) (int, error) method to MyReader.
func (r MyReader) Read(b []byte) (n int, err error) {
    for i := range b {
        b[i] = 'A'
    }
    return len(b), nil
}

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