You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: flow_graph_dmstream_input_node.go
    path of file: ./repos/milvus/internal/datanode
    
    the code of the file until where you have to start completion: // Licensed to the LF AI & Data foundation under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package datanode

import (
	"context"
	"fmt"
	"time"

	"go.uber.org/zap"

	"github.com/milvus-io/milvus-proto/go-api/v2/msgpb"
	"github.com/milvus-io/milvus/internal/util/flowgraph"
	"github.com/milvus-io/milvus/pkg/log"
	"github.com/milvus-io/milvus/pkg/metrics"
	"github.com/milvus-io/milvus/pkg/mq/msgdispatcher"
	"github.com/milvus-io/milvus/pkg/mq/msgstream"
	"github.com/milvus-io/milvus/pkg/mq/msgstream/mqwrapper"
	"github.com/milvus-io/milvus/pkg/util/paramtable"
	"github.com/milvus-io/milvus/pkg/util/tsoutil"
	"github.com/milvus-io/milvus/pkg/util/typeutil"
)

// DmInputNode receives messages from message streams, packs messages between two timetick
    
func newDmInputNode(initCtx context.Context, dispatcherClient msgdispatcher.Client, seekPos *msgpb.MsgPosition, dmNodeConfig *nodeConfig) (*flowgraph.InputNode, error) {
	log := log.With(zap.Int64("nodeID", paramtable.GetNodeID()),
		zap.Int64("collectionID", dmNodeConfig.collectionID),
		zap.String("vchannel", dmNodeConfig.vChannelName))
	var err error
	var input <-chan *msgstream.MsgPack
	if seekPos != nil && len(seekPos.MsgID) != 0 {
		input, err = dispatcherClient.Register(initCtx, dmNodeConfig.vChannelName, seekPos, mqwrapper.SubscriptionPositionUnknown)
		if err != nil {
			return nil, err
		}
		log.Info("datanode seek successfully when register to msgDispatcher",
			zap.ByteString("msgID", seekPos.GetMsgID()),
			zap.Time("tsTime", tsoutil.PhysicalTime(seekPos.GetTimestamp())),
			zap.Duration("tsLag", time.Since(tsoutil.PhysicalTime(seekPos.GetTimestamp()))))
	} else {
		input, err = dispatcherClient.Register(initCtx, dmNodeConfig.vChannelName, nil, mqwrapper.SubscriptionPositionEarliest)
		if err != nil {
			return nil, err
		}
		log.Info("datanode consume successfully when register to msgDispatcher")
	}

	name := fmt.Sprintf("dmInputNode-data-%d-%s", dmNodeConfig.collectionID, dmNodeConfig.vChannelName)
	node := flowgraph.NewInputNode(
		input,
		name,
		Params.DataNodeCfg.FlowGraphMaxQueueLength.GetAsInt32(),
		Params.DataNodeCfg.FlowGraphMaxParallelism.GetAsInt32(),
		typeutil.DataNodeRole,
		dmNodeConfig.serverID,
		dmNodeConfig.collectionID,
		metrics.AllLabel,
	)
	return node, nil
}