C# signpost stub methods

Signposts.cs

using System.Runtime.InteropServices;

public static class Signposts
{
    [DllImport ("__Internal")]
    private static extern void initialize_log_handles();

    [DllImport("__Internal")]
    public static extern ulong start_interval_load_asset(string _assetPath);

    [DllImport("__Internal")]
    public static extern void stop_interval_load_asset(ulong _signpostId);

    [DllImport("__Internal")]
    public static extern void stop_interval_load_asset_failed(ulong _signpostId);

    [DllImport("__Internal")]
    public static extern void event_input_tap(int _x, int _y);
    
    static Signposts()
    {
        initialize_log_handles();
    }
}