server: return 'terminated' error when server is terminated with Close()

server.go

@@ -343,12 +343,11 @@ func (s *Server) run() {
 		}
 	}()
 
-outer:
+	s.exitError = func() error {
 		for {
 			select {
 			case err := <-acceptErr:
-			s.exitError = err
+				return err
-			break outer
 
 			case nconn := <-connNew:
 				sc := newServerConn(s, nconn)
@@ -435,9 +434,10 @@ outer:
 				req.res <- ip
 
 			case <-s.ctx.Done():
-			break outer
+				return liberrors.ErrServerTerminated{}
 			}
 		}
+	}()
 
 	s.ctxCancel()