func (f file) WriteAt(p []byte, off int64) (n int, err error) {
	err = f.WriteAtContext(context.Background(), p, off)
	if err != nil {
		return 0, err
	}
	return len(p), nil
}
// WriteAt writes len(p) bytes from p to the file at offset off.
WriteAt writes len(p) bytes from p to the file at offset off.
// WriteAt writes len ( p ) bytes from p to the file at offset off .
func (f file) WriteAt(p []byte, off int64) (n int, err error) {
	err = f.WriteAtContext(context.Background(), p, off)
	if err != nil {
		return 0, err
	}
	return len(p), nil
}
func ( f file ) WriteAt ( p [ ] byte , off int64 ) ( n int , err error ) { err = f . WriteAtContext ( context . Background ( ) , p , off ) if err != nil { return 0 , err } return len ( p ) , nil }
WriteAt writes len(p) bytes from p to the file at offset off.
WriteAt writes len ( p ) bytes from p to the file at offset off .