file.ReadAt() always reads at offset 0

test.go

package main

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

func main() {
	file, err := os.Open("test.go")
	buffer := make([]byte, 32, 32)

	//var err error
	bytesRead := 0
	offset := int64(0)
	for bytesRead, err = file.ReadAt(buffer, offset); bytesRead > 0 && err != io.EOF; offset += int64(bytesRead) {
		fmt.Printf("%s", string(buffer[0:bytesRead]))
		fmt.Printf("%d %d\n", bytesRead, offset)
		if offset > 473 {
			fmt.Printf("Offset > EOF")
			break
		}
	}
}