WaitGroup can't wake up randomly

[cpunion]

package main

import (
	"fmt"
	"sync"
	"time"

	"github.com/goplus/llgo/c"
)

func timeout(d time.Duration) <-chan struct{} {
	ch := make(chan struct{})
	go func() {
		c.Usleep(c.Uint(d.Microseconds()))
		close(ch)
	}()
	return ch
}

func main() {
	ch := make(chan int)
	var wg sync.WaitGroup

	// Start a receiver goroutine
	go func() {
		for i := 0; i < 2; i++ {
			select {
			case v := <-ch:
				fmt.Printf("Received: %d\n", v)
			case <-timeout(time.Second):
				fmt.Println("Receive timeout")
			}
		}
	}()

	for i := 0; i < 2; i++ {
		wg.Add(1)
		go func(id int) {
			defer 
			select {
			case ch <- id:
				defer fmt.Printf("Sent value: %d\n", id)
			case <-timeout(time.Millisecond * 100):
				defer fmt.Printf("Timeout for: %d\n", id)
			}
wg.Done()
		}(i)
	}

	wg.Wait()
	close(ch) // Close the channel after all goroutines are done
}

[xushiwei]

Same as #694