fix: close the `e.canExit` channel in the `start` function

[appleboy]

Resolve

• Add a line to close the e.canExit channel in the start function

Reproduce

main.go

package main

import "log"

func main() {
    log.Println("Hello World")
}

Unable to terminate the process.

[xiantang]

LGTM

[xiantang]

causing more test cases failed reverting

[appleboy]

@xiantang I will take it again.

[xiantang]

OK for now test case is all successful. plz rebase your code from master and try it again