...
result := []int{}
wg sync.WaitGroup

exampleInsert := []int{1,2,3,4,5,6,7,8,9,10}

for i:=0; i < 100; i ++ {
	wg.add(1)
	go func() {
		defer wg.Done()
		result = append(result, exampleInsert ...)
		}
	}()
}
wg.Wait()
fmt.Println("size is not 1000! its %d", len(result))
...