1 files changed, 4 insertions, 3 deletions
diff --git a/csharp/src/Google.Protobuf/Collections/RepeatedField.cs b/csharp/src/Google.Protobuf/Collections/RepeatedField.cs
index 1cde03bc..d1db856c 100644
--- a/csharp/src/Google.Protobuf/Collections/RepeatedField.cs
+++ b/csharp/src/Google.Protobuf/Collections/RepeatedField.cs
@@ -33,6 +33,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.IO;
 using System.Text;
 
 namespace Google.Protobuf.Collections
@@ -474,9 +475,9 @@ namespace Google.Protobuf.Collections
         /// </summary>
         public override string ToString()
         {
-            var builder = new StringBuilder();
-            JsonFormatter.Default.WriteList(builder, this);
-            return builder.ToString();
+            var writer = new StringWriter();
+            JsonFormatter.Default.WriteList(writer, this);
+            return writer.ToString();
         }
 
         /// <summary>