XPNet: X-Plane reports plugin dir as D:/X-Plane11/Resources/plugins/AirlineCaptainPlugin/64
XPNet: Probing for a CLR at D:/X-Plane11/Resources/plugins/AirlineCaptainPlugin/64/dotnet-windows/shared/Microsoft.NETCore.App...NO
XPNet: Probing for a CLR at D:/X-Plane11/Resources/plugins/AirlineCaptainPlugin/dotnet-windows/shared/Microsoft.NETCore.App...FOUND
XPNet: Will load plugins from D:/X-Plane11/Resources/plugins/AirlineCaptainPlugin
XPNet: Will load CLR from: D:/X-Plane11/Resources/plugins/AirlineCaptainPlugin/dotnet-windows/shared/Microsoft.NETCore.App/2.1.17/coreclr.dll
XPNet: ClrPluginStart Result = 0.
Failed: D:\X-Plane11/Resources/plugins/AirlineCaptainPlugin/64/win.xpl. (The plugin refused to start by returning 0 from XPluginStart.)

The constructor contains:

public Plugin(IXPlaneApi api)
{
m_api = api ?? throw new ArgumentNullException(nameof(api));
}

.. which is the equivalent of the XPluginStart right?