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: reader.go
    path of file: ./repos/gitkube/vendor/cloud.google.com/go/bigtable
    
    the code of the file until where you have to start completion: /*
Copyright 2016 Google LLC

Licensed 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 bigtable

import (
	"bytes"
	"fmt"

	btpb "google.golang.org/genproto/googleapis/bigtable/v2"
)

// A Row is returned by ReadRows. The map is keyed by column family (the prefix
// of the column name before the colon). The values are the returned ReadItems
// for that column family in the order returned by Read.
type Row map[str
    
func (cr *chunkReader) Process(cc *btpb.ReadRowsResponse_CellChunk) (Row, error) {
	var row Row
	switch cr.state {
	case newRow:
		if err := cr.validateNewRow(cc); err != nil {
			return nil, err
		}

		cr.curRow = make(Row)
		cr.curKey = cc.RowKey
		cr.curFam = cc.FamilyName.Value
		cr.curQual = cc.Qualifier.Value
		cr.curTS = cc.TimestampMicros
		row = cr.handleCellValue(cc)

	case rowInProgress:
		if err := cr.validateRowInProgress(cc); err != nil {
			return nil, err
		}

		if cc.GetResetRow() {
			cr.resetToNewRow()
			return nil, nil
		}

		if cc.FamilyName != nil {
			cr.curFam = cc.FamilyName.Value
		}
		if cc.Qualifier != nil {
			cr.curQual = cc.Qualifier.Value
		}
		cr.curTS = cc.TimestampMicros
		row = cr.handleCellValue(cc)

	case cellInProgress:
		if err := cr.validateCellInProgress(cc); err != nil {
			return nil, err
		}
		if cc.GetResetRow() {
			cr.resetToNewRow()
			return nil, nil
		}
		row = cr.handleCellValue(cc)
	}

	return row, nil
}