title: UdpClient can't send many packets to different address?
body: <p>I need find devices in local network in some range of IP. Device can response on Udp datagramm. I do next:</p>
  
  <pre><code>var udpSend = new UdpClient();
  foreach (string ip in list)            
     udpSend.Send(new byte[] { 0xCE, 0x56, 0x01 },3, ip, 33333);
  </code></pre>
  
  <p>There are many addresses in list (10.0.1.1 - 10.0.255.255).
  But not all devices receive my message.
  I tryed another way:</p>
  
  <pre><code>foreach (string ip in list)
          {
              var udpSend = new UdpClient();
              udpSend.Send(new byte[] {0xCE, 0x56, 0x01}, 3, ip, 33333); 
              udp.Close();
          }
  </code></pre>
  
  <p>But after 255 packets udp.Close(); begin very slow.</p>
  
  <p>How I can create like udp scanner?</p>