[Modify] Polish it

Author: sta

websocket-sharp/Net/HttpListenerResponse.cs

@@ -349,12 +349,26 @@ public Version ProtocolVersion {
  }
 
  set {
- checkDisposedOrHeadersSent ();
+ if (_disposed)
+ throw new ObjectDisposedException (GetType ().ToString ());
+
+ if (_headersSent) {
+ var msg = "The response is already being sent.";
+ throw new InvalidOperationException (msg);
+ }
+
  if (value == null)
  throw new ArgumentNullException ("value");
 
- if (value.Major != 1 || (value.Minor != 0 && value.Minor != 1))
- throw new ArgumentException ("Not 1.0 or 1.1.", "value");
+ if (value.Major != 1) {
+ var msg = "Its Major property is not 1.";
+ throw new ArgumentException (msg, "value");
+ }
+
+ if (value.Minor < 0 || value.Minor > 1) {
+ var msg = "Its Minor property is not 0 or 1.";
+ throw new ArgumentException (msg, "value");
+ }
 
  _version = value;
  }