avoid close 'nil' panics if any (#18890)

brings a generic implementation that
prints a stack trace for 'nil' channel
closes(), if not safely closes it.

cmd/erasure-sets.go

@@ -37,6 +37,7 @@ import (
 	"github.com/minio/minio-go/v7/pkg/set"
 	"github.com/minio/minio-go/v7/pkg/tags"
 	"github.com/minio/minio/internal/dsync"
+	xioutil "github.com/minio/minio/internal/ioutil"
 	"github.com/minio/minio/internal/logger"
 	"github.com/minio/pkg/v2/console"
 	"github.com/minio/pkg/v2/sync/errgroup"
@@ -667,10 +668,10 @@ func (s *erasureSets) Shutdown(ctx context.Context) error {
 	select {
 	case _, ok := <-s.setReconnectEvent:
 		if ok {
-			close(s.setReconnectEvent)
+			xioutil.SafeClose(s.setReconnectEvent)
 		}
 	default:
-		close(s.setReconnectEvent)
+		xioutil.SafeClose(s.setReconnectEvent)
 	}
 	return nil
 }