You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: circuit_breaker_error_count_example.go
    path of file: ./repos/sentinel-golang/example/circuitbreaker/error_count
    
    the code of the file until where you have to start completion: // Copyright 1999-2020 Alibaba Group Holding Ltd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package main

import (
	"errors"
	"fmt"
	"log"
	"math/rand"
	"time"

	sentinel "github.com/alibaba/sentinel-golang/api"
	"github.com/alibaba/sentinel-golang/core/circuitbreaker"
	"github.com/alibaba/sentinel-golang/core/config"
	"github.com/alibaba/sentinel-golang/logging"
	"github.com/alibaba/sentinel-golang/util"
)

type stateChangeTestListener struct {
}

func (s *stateChangeTestListener) OnTransformToClosed(prev circuitbreaker.State, rule circuitbreaker.Rule) {
	fmt.Printf("rule.steategy: %+v, From %s to Closed, time: %d\n", rule.Strategy, prev.String(), util.CurrentTimeMillis())
}

func (s *stateChangeTestListener) OnTransformToOpen(prev circuitbreaker.State, rule circuitbreaker.Rule, snapshot interface{}) {
	fmt.Printf("rule.steategy: %+v, From %s to Open, snapshot: %d, time: %d\n", rule.Strategy, prev.String(), snapshot, util.CurrentTimeMillis())
}

func (s *stateChangeTestListener) OnTransformToHalfOpen(prev circuitbre
    
func main() {
	conf := config.NewDefaultConfig()
	// for testing, logging output to console
	conf.Sentinel.Log.Logger = logging.NewConsoleLogger()
	err := sentinel.InitWithConfig(conf)
	if err != nil {
		log.Fatal(err)
	}
	ch := make(chan struct{})
	// Register a state change listener so that we could observer the state change of the internal circuit breaker.
	circuitbreaker.RegisterStateChangeListeners(&stateChangeTestListener{})

	_, err = circuitbreaker.LoadRules([]*circuitbreaker.Rule{
		// Statistic time span=5s, recoveryTimeout=3s, maxErrorCount=50
		{
			Resource:                     "abc",
			Strategy:                     circuitbreaker.ErrorCount,
			RetryTimeoutMs:               3000,
			MinRequestAmount:             10,
			StatIntervalMs:               5000,
			StatSlidingWindowBucketCount: 10,
			Threshold:                    50,
		},
	})
	if err != nil {
		log.Fatal(err)
	}

	logging.Info("[CircuitBreaker ErrorCount] Sentinel Go circuit breaking demo is running. You may see the pass/block metric in the metric log.")
	go func() {
		for {
			e, b := sentinel.Entry("abc")
			if b != nil {
				// g1 blocked
				time.Sleep(time.Duration(rand.Uint64()%20) * time.Millisecond)
			} else {
				if rand.Uint64()%20 > 9 {
					// Record current invocation as error.
					sentinel.TraceError(e, errors.New("biz error"))
				}
				// g1 passed
				time.Sleep(time.Duration(rand.Uint64()%80+10) * time.Millisecond)
				e.Exit()
			}
		}
	}()
	go func() {
		for {
			e, b := sentinel.Entry("abc")
			if b != nil {
				// g2 blocked
				time.Sleep(time.Duration(rand.Uint64()%20) * time.Millisecond)
			} else {
				// g2 passed
				time.Sleep(time.Duration(rand.Uint64()%80) * time.Millisecond)
				e.Exit()
			}
		}
	}()
	<-ch
}