.NET MongoDB + Realm Sync models demonstrating relationships and embedded objects

Comment.cs

using System;
using Realms;

namespace RealmDev.Core.RealmObjects
{
    public class Comment : EmbeddedObject
    {
        public DateTimeOffset CreatedOn { get; set; }
        public string Text { get; set; }
        public string Author { get; set; }
    }
}

Contractor.cs

using System.Linq;
using MongoDB.Bson;
using MongoDB.Bson.Serialization.Attributes;
using Realms;

namespace RealmDev.Core.RealmObjects
{
    public class Contractor : RealmObject
    {
        [PrimaryKey]
        [MapTo("_id")]
        public ObjectId Id { get; set; } = ObjectId.GenerateNewId();

        [MapTo("_partition")]
        [Required]
        public string Partition { get; set; }

        [MapTo("name")]
        [Required]
        public string Name { get; set; }

        [MapTo("title")]
        [Required]
        public string Title { get; set; }

        // To-many relationship
        [Backlink(nameof(Issue.Assignee))]
        public IQueryable<Issue> Issues { get; }
    }
}

Document.cs

public class Document : RealmObject, IDocument
{
    [PrimaryKey]
    [MapTo("_id")]
    public ObjectId Id { get; set; }  = ObjectId.GenerateNewId();

    [MapTo("_partition")]
    [Required]
    public string Partition { get; set; }

    [Required]
    public string Name { get; set; }

    // Back-linked relationship
    public Folder Folder { get; set; }
}

Folder.cs

using System.Collections.Generic;
using MongoDB.Bson;
using MongoDB.Bson.Serialization.Attributes;
using RealmDev.Core.Interfaces.Browse;
using Realms;

namespace RealmDev.Core.RealmObjects.Browse
{
    public class Folder : RealmObject, IFolder
    {
        [PrimaryKey]
        [MapTo("_id")]
        public ObjectId Id { get; set; }  = ObjectId.GenerateNewId();

        [MapTo("_partition")]
        [Required]
        public string Partition { get; set; }

        [Required]
        public string Name { get; set; }

        // Back-linked relationship
        public Folder ParentFolder { get; set; }

        // To-many relationship
        public IList<Folder> Folders { get; }

        // To-many relationship
        public IList<Document> Documents { get; }

        [BsonIgnore] public IEnumerable<IFolder> FolderItems => Folders;

        [BsonIgnore] public IEnumerable<IDocument> DocumentItems => Documents;

        [BsonIgnore] public IFolder Parent => ParentFolder;

        [BsonIgnore] public string Key => Id.ToString();
    }
}

Issue.cs

using System;
using System.Collections.Generic;
using System.Linq;
using MongoDB.Bson;
using MongoDB.Bson.Serialization.Attributes;
using RealmDev.Core.Enums;
using RealmDev.Core.Interfaces.Issues;
using Realms;

namespace RealmDev.Core.RealmObjects
{
    public class Issue : RealmObject, IIssue
    {
        [PrimaryKey]
        [MapTo("_id")]
        public ObjectId Id { get; set; }  = ObjectId.GenerateNewId();

        [MapTo("_partition")]
        [Required]
        public string Partition { get; set; }

        [Required]
        public string Description { get; set; }

        public DateTimeOffset CreatedOn { get; set; }

        public int StatusId { get; set; }

        [BsonIgnore]
        public IssueStatus Status
        {
            get => (IssueStatus)StatusId;
            set => StatusId = (int)value;
        }

        // Embedded objects
        public IssuePriority Priority { get; set; }
        public IList<Comment> Comments { get; }
        public IList<Photo> Photos { get; }
        public IList<IssueHistory> History { get; }

        // Back-linked relationship
        public Contractor Assignee { get; set; }
    }
}

IssueHistory.cs

public class IssueHistory : EmbeddedObject
{
    public DateTimeOffset CreatedOn { get; set; }

    public IssueStatus Status
    {
        get => (IssueStatus)StateId;
        set => StateId = (int)value;
    }

    public int StateId { get; set; }

    public string ByUser { get; set; }
}

IssuePriority.cs

public class IssuePriority : EmbeddedObject
{
    public ObjectId Id { get; set; }

    public int ValueId { get; set; }

    [BsonIgnore]
    public Enums.Priority Value
    {
        get => (Enums.Priority)ValueId;
        set => ValueId = (int)value;
    }
}

Photo.cs

public class Photo : EmbeddedObject
{
    public DateTimeOffset CreatedOn { get; set; }
    public string Url { get; set; }
    public string FileName { get; set; }
    public string Author { get; set; }
}