reqres.go
func (r *reqResReader) arg2Reader() (ArgReader, error) {
	return r.argReader(false /* last */, reqResReaderPreArg2, reqResReaderPreArg3)
}
func (r *reqResReader) arg2Reader() (ArgReader, error) {
	return r.argReader(false /* last */, reqResReaderPreArg2, reqResReaderPreArg3)
}
// arg2Reader returns an ArgReader to read arg2.