func DeregisterTLSConfig(key string) {
	if tlsConfigRegister != nil {
		delete(tlsConfigRegister, key)
	}
}
DeregisterTLSConfig removes the tls.Config associated with key.
package mysql
import (
	"crypto/sha1"
	"crypto/tls"
	"database/sql/driver"
	"encoding/binary"
	"fmt"
	"io"
	"strings"
	"time"
)
var (
	tlsConfigRegister map[string]*tls.Config  
)
func RegisterTLSConfig(key string, config *tls.Config) error {
	if _, isBool := readBool(key); isBool || strings.ToLower(key) == "skip-verify" {
		return fmt.Errorf("key '%s' is reserved", key)
	}
	if tlsConfigRegister == nil {
		tlsConfigRegister = make(map[string]*tls.Config)
	}
	tlsConfigRegister[key] = config
	return nil
}