Demo - channel is blocked with tuple form if its open and unbuffered

code.go

package main

import (
	"strconv"
	"time"
)

func main() {
	c := make(chan string)
	w := make(chan struct{})
	f := func() {
		print("top")
		_, more := <-c
		print("bottom")
		print(strconv.FormatBool(more))
		if more {
			print(" channel is open\n")
		} else {
			print(" channel is closed\n")
		}
		w <- struct{}{}
	}
	go f()
	print("func should be blocked\n")
	time.Sleep(time.Second)
	c <- "not ok"
	close(c)
	go f()
	<-w
	<-w
}