Throw InvalidOperationException in TcpClientSession.Connect() instead of Exception()

[jamesmcguirepro]

When connect() is called on a TcpClientSession that is already connected or in process of being connected, an InvalidOperationException should be thrown, not a generic Exception.

SuperSocket.ClientEngine/Core/TcpClientSession.cs

Line 107 in 6f02bd6

throw new Exception("The socket is connecting, cannot connect again!");

SuperSocket.ClientEngine/Core/TcpClientSession.cs

Line 110 in 6f02bd6

throw new Exception("The socket is connected, you needn't connect again!");

This mimics System.Net.Socket.ConnectAsync()'s exceptions:
https://docs.microsoft.com/en-us/dotnet/api/system.net.sockets.socket.connectasync?view=netframework-4.8