func (b *VarHeatmapColumnType) Serialize(v interface{}) ([]byte, error) {
	buff := new(bytes.Buffer)
	e := gob.NewEncoder(buff)
	err := e.Encode(v)
	if err != nil {
		return nil, err
	}
	return buff.Bytes(), nil
}
Serialize serializes this VarHeatmapColumnType to binary data
package integration
import (
	"bufio"
	"bytes"
	"context"
	"encoding/gob"
	"fmt"
	"image"
	"image/color"
	"image/draw"
	"image/png"
	"math"
	"os"
	"path"
	"testing"
	"github.com/go-sif/sif"
	"github.com/go-sif/sif/cluster"
	"github.com/go-sif/sif/datasource/file"
	dsv "github.com/go-sif/sif/datasource/parser/dsv"
	ops "github.com/go-sif/sif/operations/transform"
	util "github.com/go-sif/sif/operations/util"
	"github.com/go-sif/sif/schema"
	siftest "github.com/go-sif/sif/testing"
	"github.com/stretchr/testify/require"
	"go.uber.org/goleak"
)
func createTestNYCTaxiDataFrame(t *testing.T) sif.DataFrame {
	schema := schema.CreateSchema()
	schema.CreateColumn("hack", &sif.StringColumnType{Length: 32})
	schema.CreateColumn("license", &sif.StringColumnType{Length: 32})
	schema.CreateColumn("code", &sif.StringColumnType{Length: 3})
	schema.CreateColumn("flag", &sif.Uint8ColumnType{})
	schema.CreateColumn("type", &sif.VarStringColumnType{})
	schema.CreateColumn("pickup_time", &sif.VarStringColumnType{})
	schema.CreateColumn("dropoff_time", &sif.VarStringColumnType{})
	schema.CreateColumn("passengers", &sif.Uint8ColumnType{})
	schema.CreateColumn("duration", &sif.Uint32ColumnType{})
	schema.CreateColumn("distance", &sif.Float32ColumnType{})
	schema.CreateColumn("pickup_lon", &sif.Float64ColumnType{})
	schema.CreateColumn("pickup_lat", &sif.Float64ColumnType{})
	schema.CreateColumn("dropoff_lon", &sif.Float64ColumnType{})
	schema.CreateColumn("dropoff_lat", &sif.Float64ColumnType{})
	cwd, err := os.Getwd()
	require.Nil(t, err)
	parser := dsv.CreateParser(&dsv.ParserConf{
		NilValue: "null",
	})
	conf := &file.DataSourceConf{Glob: path.Join(cwd, "../../../testenv/*.csv")}
	dataframe := file.CreateDataFrame(conf, parser, schema)
	return dataframe
}
type VarHeatmapColumnType struct {
}
func (b *VarHeatmapColumnType) Size() int {
	return 0
}
func (b *VarHeatmapColumnType) ToString(v interface{}) string {
	return "[HEATMAP]"
}