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: main.go
    path of file: ./repos/go-profiler-notes/examples/block-sample
    
    the code of the file until where you have to start completion: package main

import (
	"context"
	"fmt"
	"os"
	"runtime"
	"runtime/pprof"
	"time"

	"golang.org/x/sync/errgroup"
)

func main() {
	if err := run(); err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
}

func run() error {
	labels := pprof.Labels("test_label", "test_value")
	ctx := pprof.WithLabels(context.Background()
    
func simulateBlockEvents(meanDuration time.Duration, done chan struct{}) error {
	var (
		prev   time.Time
		sum    time.Duration
		count  int
		ticker = time.NewTicker(meanDuration)
	)
	defer ticker.Stop()
	for {
		select {
		case <-ticker.C:
			now := time.Now()
			if !prev.IsZero() {
				sum += now.Sub(prev)
				count += 1
				if count > 1000 {
					actualMean := float64(sum) / float64(count)
					max := tolerance * float64(meanDuration)
					min := float64(meanDuration) / tolerance
					if actualMean <= min || actualMean >= max {
						return fmt.Errorf("low clock accuracy: got=%s want=%s", time.Duration(actualMean), meanDuration)
					}
				}
			}
			prev = now
		case <-done:
			return nil
		}
	}
}