From bc5d4074771583ecb692c05752658ebfbd6e342a Mon Sep 17 00:00:00 2001
From: Devon Carew <devoncarew@google.com>
Date: Wed, 1 Jun 2016 19:57:08 -0700
Subject: [PATCH] fix an issue where the refresh benchmark would overwrite a
 completer (#4315)

---
 packages/flutter_tools/lib/src/observatory.dart | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/flutter_tools/lib/src/observatory.dart b/packages/flutter_tools/lib/src/observatory.dart
index 5e7a77897c..7bcc8e145b 100644
--- a/packages/flutter_tools/lib/src/observatory.dart
+++ b/packages/flutter_tools/lib/src/observatory.dart
@@ -83,7 +83,7 @@ class Observatory {
     if (isolates.isNotEmpty)
       return isolates.first;
 
-    _waitFirstIsolateCompleter = new Completer<IsolateRef>();
+    _waitFirstIsolateCompleter ??= new Completer<IsolateRef>();
 
     getVM().then((VM vm) {
       for (IsolateRef isolate in vm.isolates)