fragmenting_reader.go
func (r *fragmentingReader) ArgReader(last bool) (ArgReader, error) {
	if err := r.BeginArgument(last); err != nil {
		return nil, err
	}
	return r, nil
}
func (r *fragmentingReader) ArgReader(last bool) (ArgReader, error) {
	if err := r.BeginArgument(last); err != nil {
		return nil, err
	}
	return r, nil
}
// The ArgReader will handle fragmentation as needed. Once the argument has
// been read, the ArgReader must be closed.