From 889e6d30b6b5f9ff3cf19f00706c741e8cd7bff3 Mon Sep 17 00:00:00 2001
From: sta <sta.blockhead@gmail.com>
Date: Sat, 21 Dec 2019 22:10:26 +0900
Subject: [PATCH] [Modify] Throw an exception

---
 websocket-sharp/Net/HttpListenerResponse.cs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/websocket-sharp/Net/HttpListenerResponse.cs b/websocket-sharp/Net/HttpListenerResponse.cs
index 0c72b565..a49e3ed0 100644
--- a/websocket-sharp/Net/HttpListenerResponse.cs
+++ b/websocket-sharp/Net/HttpListenerResponse.cs
@@ -568,6 +568,11 @@ namespace WebSocketSharp.Net
         if (_disposed)
           throw new ObjectDisposedException (GetType ().ToString ());
 
+        if (_headersSent) {
+          var msg = "The response is already being sent.";
+          throw new InvalidOperationException (msg);
+        }
+
         if (value == null) {
           _location = null;
           return;