/// <summary>
 /// This method returns server singleton with specified port.
 /// </summary>
 /// <param name="socketAddress">IP:PORT that user enters</param>
 /// <returns>Server singleton with specified port</returns>
 public static Server getInstance(string socketAddress)
 {
     if (serverInstance == null)
     {
         serverInstance = new Server(socketAddress);
     }
     return serverInstance;
 }
 /// <summary>
 /// Factory method.
 /// </summary>
 /// <returns>Server with port '8080' </returns>
 public static Server getInstance()
 {
     if (serverInstance == null)
     {
         serverInstance = new Server();
     }
     
     return serverInstance;
 }