func _D(fmt string, v ...interface{}) {
	if DEBUG {
		log.Printf(fmt, v...)
	}
}
called for debug output
package main
import (
	"bytes"
	"crypto/tls"
	"crypto/x509"
	"errors"
	"flag"
	"github.com/miekg/dns"
	"io/ioutil"
	"log"
	"math/rand"
	"net"
	"net/http"
	"strings"
	"sync"
	"time"
)
var DEBUG bool = false