func OmitProgLabel() Option {
	return func(e *Exporter) error {
		e.omitProgLabel = true
		return nil
	}
}
OmitProgLabel sets the Exporter to not put program names in metric labels.
package exporter
import (
	"context"
	"expvar"
	"flag"
	"fmt"
	"io"
	"net"
	"os"
	"strings"
	"sync"
	"time"
	"github.com/golang/glog"
	"github.com/google/mtail/internal/metrics"
	"github.com/pkg/errors"
)
var (
	writeDeadline = flag.Duration("metric_push_write_deadline", 10*time.Second, "Time to wait for a push to succeed before exiting with an error.")
)
type Exporter struct {
	ctx           context.Context
	wg            sync.WaitGroup
	store         *metrics.Store
	pushInterval  time.Duration
	hostname      string
	omitProgLabel bool
	emitTimestamp bool
	pushTargets   []pushOptions
	initDone      chan struct{}
}
type Option func(*Exporter) error
func Hostname(hostname string) Option {
	return func(e *Exporter) error {
		e.hostname = hostname
		return nil
	}
}