package main

import (
        "fmt"
        "math"
        "time"
)

func main() {
        var m = make(map[int32]bool)

        go func() {
                for {
                        for k, v := range m {
                                if k == 0 {
                                        fmt.Println(k, v)
                                        panic(fmt.Errorf("No! got 0! key should >= 1 !"))
                                }
                                time.Sleep(1 * time.Millisecond)
                        }
                }
        }()
        i := int32(1) // make sure key>=1
        for i < math.MaxInt32 {
                m[i] = true
                delete(m, i)
                i++
                time.Sleep(1 * time.Millisecond)
        }
}

0 false
panic: No! got 0! key should >= 1 !

goroutine 5 [running]:
panic(0x490fe0, 0xc42000a3b0)
        /opt/go/src/runtime/panic.go:500 +0x1a1
main.main.func1(0xc420014210)
        /home/caspian/goprojects/src/testmap.go:17 +0x1c8
created by main.main
        /home/caspian/goprojects/src/testmap.go:22 +0x73
exit status 2