TopShelf Exit Code Guidance

[robdmoore]

We should remember to publish guidance about making the exit code from the topshelf app right be returning, in fact I had this:

    private static readonly TopshelfExitCode[] OkStatuses = new[]
    {
        TopshelfExitCode.Ok, TopshelfExitCode.ServiceAlreadyInstalled, TopshelfExitCode.ServiceAlreadyRunning, TopshelfExitCode.ServiceNotInstalled
    };

...

    static int Main()
    {
        ...
        var exitCode = HostFactory.Run(x =>
        {
            ...
        };

        return OkStatuses.Contains(exitCode)
            ? 0
            : (int)exitCode;
    }