func TestCallbacksRemove(t *testing.T) {
	db, _ := gorm.Open(nil, nil)
	createCallback := db.Callback().Create()

	createCallback.Before("*").Register("c1", c1)
	createCallback.After("*").Register("c2", c2)
	createCallback.Before("c4").Register("c3", c3)
	createCallback.After("c2").Register("c4", c4)

	// callbacks: []string{"c1", "c3", "c4", "c2"}
	createCallback.Remove("c1")

}

func (p *processor) Match(fc func(*DB) bool) *callback {
	return &callback{match: fc, processor: p}
}

func (p *processor) Register(name string, fn func(*DB)) error {
	return (&callback{processor: p}).Register(name, fn)
}

func (p *processor) Remove(name string) error {
	return (&callback{processor: p}).Remove(name)
}

// If the host does not exist nil will be returned.
func (m *Manager) Connection(host string) *Connection {
	return m.targets[host]
}

// RegisterSingleHandler will register a stateless handler that serves
// []byte -> ([]byte, error) requests.
// subroutes are joined with "/" to a single subroute.
func (m *Manager) RegisterSingleHandler(id HandlerID, h SingleHandlerFn, subroute ...string) error {

	"context"
	"database/sql"
	"database/sql/driver"
	"encoding/gob"
	"encoding/json"
	"fmt"
	"reflect"
	"strings"
	"sync"
	"time"
)

var serializerMap = sync.Map{}

// RegisterSerializer register serializer
func RegisterSerializer(name string, serializer SerializerInterface) {
	serializerMap.Store(strings.ToLower(name), serializer)
}

// GetSerializer get serializer

// registerBootstrapRESTHandlers - register bootstrap rest router.
func registerBootstrapRESTHandlers(gm *grid.Manager) {
	server := &bootstrapRESTServer{}
	logger.FatalIf(serverVerifyHandler.Register(gm, server.VerifyHandler), "unable to register handler")
}

// client to talk to bootstrap NEndpoints.
type bootstrapRESTClient struct {

func registerDistErasureRouters(router *mux.Router, endpointServerPools EndpointServerPools) {
	// Register storage REST router only if its a distributed setup.
	registerStorageRESTHandlers(router, endpointServerPools, globalGrid.Load())

	// Register peer REST router only if its a distributed setup.
	registerPeerRESTHandlers(router, globalGrid.Load())

	// Register bootstrap REST router for distributed setups.
	registerBootstrapRESTHandlers(globalGrid.Load())

)

const (
	// Location to read istioctl defaults from
	defaultIstioctlConfig = "$HOME/.istioctl/config.yaml"
)

var (
	// IstioConfig is the name of the istioctl config file (if any)
	IstioConfig = env.Register("ISTIOCONFIG", defaultIstioctlConfig,
		"Default values for istioctl flags").Get()

	LoggingOptions = defaultLogOptions()

	metricsRouter.Handle(prometheusMetricsV2ResourcePath, auth(metricsResourceHandler()))

	// Metrics v3!
	metricsV3Server := newMetricsV3Server(authType)

	// Register metrics v3 handler. It also accepts an optional query
	// parameter `?list` - see handler for details.
	metricsRouter.Methods(http.MethodGet).Path(metricsV3Path + "{pathComps:.*}").Handler(metricsV3Server)

			// allowed number of typed errors
			if words.DamerauLevenshteinDistance(command, value) < 2 {
				closestCommands = append(closestCommands, value)
			}
		}

		return closestCommands
	}

	// Register all commands.
	registerCommand(serverCmd)

	// Set up app.
	cli.HelpFlag = cli.BoolFlag{
		Name:  "help, h",
		Usage: "show help",
	}
	cli.VersionPrinter = printMinIOVersion