func newLazyCallReq(f *Frame) lazyCallReq {
	if msgType := f.Header.messageType; msgType != messageTypeCallReq {
		panic(fmt.Errorf("newLazyCallReq called for wrong messageType: %v", msgType))
	}

	cr := lazyCallReq{Frame: f}

	serviceLen := f.Payload[_serviceLenIndex]
	// nh:1 (hk~1 hv~1){nh}
	headerStart := _serviceLenIndex + 1 /* length byte */ + serviceLen
	numHeaders := int(f.Payload[headerStart])
	cur := int(headerStart) + 1
	for i := 0; i < numHeaders; i++ {
		keyLen := int(f.Payload[cur])
		cur++
		key := f.Payload[cur : cur+keyLen]
		cur += keyLen

		valLen := int(f.Payload[cur])
		cur++
		val := f.Payload[cur : cur+valLen]
		cur += valLen

		if bytes.Equal(key, _callerNameKeyBytes) {
			cr.caller = val
		} else if bytes.Equal(key, _routingDelegateKeyBytes) {
			cr.delegate = val
		} else if bytes.Equal(key, _routingKeyKeyBytes) {
			cr.key = val
		}
	}

	// csumtype:1 (csum:4){0,1} arg1~2 arg2~2 arg3~2
	checkSumType := ChecksumType(f.Payload[cur])
	cur += 1 /* checksum */ + checkSumType.ChecksumSize()

	// arg1~2
	arg1Len := int(binary.BigEndian.Uint16(f.Payload[cur : cur+2]))
	cur += 2
	cr.method = f.Payload[cur : cur+arg1Len]
	return cr
}
func newLazyCallReq(f *Frame) lazyCallReq {
	if msgType := f.Header.messageType; msgType != messageTypeCallReq {
		panic(fmt.Errorf("newLazyCallReq called for wrong messageType: %v", msgType))
	}

	cr := lazyCallReq{Frame: f}

	serviceLen := f.Payload[_serviceLenIndex]
	// nh:1 (hk~1 hv~1){nh}
	headerStart := _serviceLenIndex + 1 /* length byte */ + serviceLen
	numHeaders := int(f.Payload[headerStart])
	cur := int(headerStart) + 1
	for i := 0; i < numHeaders; i++ {
		keyLen := int(f.Payload[cur])
		cur++
		key := f.Payload[cur : cur+keyLen]
		cur += keyLen

		valLen := int(f.Payload[cur])
		cur++
		val := f.Payload[cur : cur+valLen]
		cur += valLen

		if bytes.Equal(key, _callerNameKeyBytes) {
			cr.caller = val
		} else if bytes.Equal(key, _routingDelegateKeyBytes) {
			cr.delegate = val
		} else if bytes.Equal(key, _routingKeyKeyBytes) {
			cr.key = val
		}
	}

	// csumtype:1 (csum:4){0,1} arg1~2 arg2~2 arg3~2
	checkSumType := ChecksumType(f.Payload[cur])
	cur += 1 /* checksum */ + checkSumType.ChecksumSize()

	// arg1~2
	arg1Len := int(binary.BigEndian.Uint16(f.Payload[cur : cur+2]))
	cur += 2
	cr.method = f.Payload[cur : cur+arg1Len]
	return cr
}
// TODO: Consider pooling lazyCallReq and using pointers to the struct.