[Golang]为什么bufio阅读器会更改字符串阅读器？

The code follows ==

s := strings.NewReader("ABCDEFGJHIJK")
fmt.Printf("pa is %d
 ", s.GetValueI()) //GetValueI() returns the value of r.i

br := bufio.NewReader(s)
fmt.Printf("papa is %d
 ", s.GetValueI())

cc, _ := br.ReadByte()
fmt.Printf("%c
", cc)
fmt.Printf("papapa is %d
 ", s.GetValueI())

The prints shows: pa is 0 papa is 0 A papapa is 12

So weired Results.. why papapa is 12 when bufio call ReadByte() ? It really confuse me a lot ..

The point of a buffered reader is to read the data stream more efficiently, no matter what size reads are requested.

When you call ReadByte, if the internal buffer is empty, it calls its internal fill() method to refill the buffer, which in this case consumes the entire strings.Reader. The single byte is then returned from this internal buffer.