proxy/grpcproxy/leader.go
func (l *leader) gotLeader() {
	l.mu.Lock()
	defer l.mu.Unlock()
	select {
	case <-l.leaderc:
		l.leaderc = make(chan struct{})
	default:
	}
}
func (l *leader) gotLeader() {
	l.mu.Lock()
	defer l.mu.Unlock()
	select {
	case <-l.leaderc:
		l.leaderc = make(chan struct{})
	default:
	}
}
// gotLeader will force update the leadership status to having a leader.