StartKeepAlive not working.

[WATYF]

Turning off KeepAlive and then turning it back on again doesn't work because StartKeepAlive doesn't flip the keepAlive bool back to true, so when KeepAliveThreadFunc starts running again, it never issues the NoopCmd because it first checks to see if keepAlive is true. You have to change StartKeepAlive to:

    public void StartKeepAlive()
    {
        CheckConnection();

        if (keepAliveThread != null)
            throw new FTPException("KeepAlive already started");
        keepAlive = true;
        keepAliveThread = new Thread(new ThreadStart(KeepAliveThreadFunc));
        keepAliveThread.Start();
    }