From a954821b9804464f89dc033f65c18af217cb6d61 Mon Sep 17 00:00:00 2001
From: Roman Khimov <roman@nspcc.ru>
Date: Fri, 2 Apr 2021 12:50:46 +0300
Subject: [PATCH] consensus: make Shutdown a no-op if not started

It makes client code a bit simpler, we can just issue a Shutdown() request
without thinking much about it (but only once of course).
---
 pkg/consensus/consensus.go | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/pkg/consensus/consensus.go b/pkg/consensus/consensus.go
index 2ced9fca8..6fc898047 100644
--- a/pkg/consensus/consensus.go
+++ b/pkg/consensus/consensus.go
@@ -252,8 +252,10 @@ func (s *service) Start() {
 
 // Shutdown implements Service interface.
 func (s *service) Shutdown() {
-	close(s.quit)
-	<-s.finished
+	if s.started.Load() {
+		close(s.quit)
+		<-s.finished
+	}
 }
 
 func (s *service) eventLoop() {