From bb790904086e99d5764805ea9c4011e9dd2adf97 Mon Sep 17 00:00:00 2001
From: sta <sta.blockhead@gmail.com>
Date: Sun, 15 Mar 2020 22:23:46 +0900
Subject: [PATCH] [Modify] Polish it

---
 websocket-sharp/Net/WebHeaderCollection.cs | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/websocket-sharp/Net/WebHeaderCollection.cs b/websocket-sharp/Net/WebHeaderCollection.cs
index 5de951d1..b108002a 100644
--- a/websocket-sharp/Net/WebHeaderCollection.cs
+++ b/websocket-sharp/Net/WebHeaderCollection.cs
@@ -826,13 +826,20 @@ namespace WebSocketSharp.Net
       if (_state == HttpHeaderType.Unspecified)
         return;
 
-      if (response && _state == HttpHeaderType.Request)
-        throw new InvalidOperationException (
-          "This collection has already been used to store the request headers.");
+      if (response) {
+        if (_state == HttpHeaderType.Response)
+          return;
 
-      if (!response && _state == HttpHeaderType.Response)
-        throw new InvalidOperationException (
-          "This collection has already been used to store the response headers.");
+        var msg = "This collection has already been used for the request headers.";
+
+        throw new InvalidOperationException (msg);
+      }
+
+      if (_state == HttpHeaderType.Response) {
+        var msg = "This collection has already been used for the response headers.";
+
+        throw new InvalidOperationException (msg);
+      }
     }
 
     private static string checkValue (string value)