Support force pseudo-terminal allocation(the ssh -f option)

public class SshCommand : IDisposable
{
    ......
    private readonly bool _forcePseudoTerminal;

    internal SshCommand(ISession session, string commandText, Encoding encoding, bool forcePseudoTerminal)
    {
        ......
        _forcePseudoTerminal = forcePseudoTerminal;
    }

    public IAsyncResult BeginExecute(AsyncCallback callback, object state)
    {
        ......
        _channel = CreateChannel();
        _channel.Open();
        if (_forcePseudoTerminal)
            _channel.SendPseudoTerminalRequest(string.Empty, 0, 0, 0, 0, null);
        _channel.SendExecRequest(CommandText);
        return _asyncResult;
    }
}

Start by locating SshCommand, its constructor, BeginExecute, and CreateChannel, then inspect how SendPseudoTerminalRequest is exposed and tested. The issue's proposed flow indicates that a force-pseudo-terminal option should be carried into execution and trigger the request before SendExecRequest; done means the option is available and behaves accordingly.