child/child.go
func (c *Child) ExitCh() <-chan int {
	c.RLock()
	defer c.RUnlock()
	return c.exitCh
}
func (c *Child) ExitCh() <-chan int {
	c.RLock()
	defer c.RUnlock()
	return c.exitCh
}
// ExitCh returns the current exit channel for this child process. This channel
// may change if the process is restarted, so implementers must not cache this
// value.