Build WebSocket Handshake

gistfile1.cs

string line = ClientHandshakeLines.FirstOrDefault(l => l.Contains("Sec-WebSocket-Key:"));
if (!string.IsNullOrEmpty(line))
{
    Handshake = "HTTP/1.1 101 Switching Protocols" + Environment.NewLine;
    Handshake += "Upgrade: websocket" + Environment.NewLine;
    Handshake += "Connection: Upgrade" + Environment.NewLine;
    Handshake += "Sec-WebSocket-Accept: "; 
    Handshake += ComputeWebSocketHandshakeSecurityHash09(line.Substring(line.IndexOf(":") + 2));
    Handshake += Environment.NewLine;
    Handshake += Environment.NewLine;
}