From 617659db6b9560d65f07863ec1e4ce3d62ca84c7 Mon Sep 17 00:00:00 2001
From: sta <sta.blockhead@gmail.com>
Date: Sun, 8 Mar 2020 22:13:30 +0900
Subject: [PATCH] [Modify] Polish it

---
 websocket-sharp/Net/WebHeaderCollection.cs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/websocket-sharp/Net/WebHeaderCollection.cs b/websocket-sharp/Net/WebHeaderCollection.cs
index a81c9258..2b943019 100644
--- a/websocket-sharp/Net/WebHeaderCollection.cs
+++ b/websocket-sharp/Net/WebHeaderCollection.cs
@@ -842,8 +842,11 @@ namespace WebSocketSharp.Net
         throw new ArgumentOutOfRangeException ("value", msg);
       }
 
-      if (!IsHeaderValue (value))
-        throw new ArgumentException ("Contains invalid characters.", "value");
+      if (!IsHeaderValue (value)) {
+        var msg = "It contains an invalid character.";
+
+        throw new ArgumentException (msg, "value");
+      }
 
       return value;
     }