Couchbase 2.0 build 19, save document don't work as in build 18


I wrote this code which worked with th db18 version of couchbase Lite 2.0, .net c# :

document = new Document("airline_88888");
        airline = new Airline();
        airline.Type = "airline";
        airline.Id = 88888;
        airline.Name = "Steeve";
        airline.Country = "France";
        document.Set("airline_88888", airline);

Since the bd19 vresion, I’ve an exception when I try to save the document :
$exception {System.InvalidCastException: Cannot encode Persistance.Airline to Fleece!
at LiteCore.Interop.FLSliceExtensions.FLEncode(Object obj, FLEncoder* enc)
at LiteCore.Interop.FLSliceExtensions.FLEncode[TVal](IDictionary`2 dict, FLEncoder* enc)
at Couchbase.Lite.Internal.Doc.InMemoryDictionary.FLEncode(FLEncoder* enc)
at LiteCore.Interop.FLSliceExtensions.FLEncode(Object obj, FLEncoder* enc)
at Couchbase.Lite.Document.Encode()
at Couchbase.Lite.Document.SaveInto(C4Document** outDoc, Boolean deletion)
at Couchbase.Lite.Document.Save(IConflictResolver resolver, Boolean deletion)
at Couchbase.Lite.Document.b__23_0()
at Couchbase.Lite.Support.ThreadSafety.DoLocked(Action a)
at Couchbase.Lite.Document.Save()
at Couchbase.Lite.Database.<>c__DisplayClass64_0.b__0()
at Couchbase.Lite.Support.ThreadSafety.DoLocked(Action a)
at Couchbase.Lite.Database.Save(Document document)
at Persistance.CouchbaseHelper.AddAirlineDocument(Airline airline, Database db)
at CouchBaseT2.MainPage.BtnAdd_Clicked(Object sender, EventArgs e)
at Xamarin.Forms.Button.SendClicked()
at Xamarin.Forms.Platform.UWP.ButtonRenderer.OnButtonClick(Object sender, RoutedEventArgs e)} System.InvalidCastException

Here is my Airline Class :

public partial class Airline
    public string Callsign { get; set; }

    public string Country { get; set; }

    public string Iata { get; set; }

    public string Icao { get; set; }

    public long Id { get; set; }

    public string Name { get; set; }

    public string Type { get; set; }

    public string Infos { get => $"{Id} - {Country} - {Name}"; }

How to save a document ?



This post discusses a similar issue. The short of it is this
From @borrrden
Saving your own custom classes into a document is not supported. Working before was just luck. We will bring the model class to the library in a future release but for now you need to convert your messages to dictionaries first."