java.lang.IllegalStateException: Cannot change table to embedded without backlink columns. Table must be embedded in at least one other table.
at io.realm.internal.Table.nativeSetEmbedded(Native Method)
at io.realm.internal.Table.setEmbedded(Table.java:725)
at io.realm.RealmObjectSchema.setEmbedded(RealmObjectSchema.java:459)
at com.blueapron.service.cache.MigrationManager$UpgradeFrom108.migrate(MigrationManager.java:1092)
at com.blueapron.service.cache.MigrationManager.migrate_inner(MigrationManager.java:131)
at com.blueapron.service.cache.MigrationManager.migrate(MigrationManager.java:116)
at io.realm.BaseRealm$6.onMigrationNeeded(BaseRealm.java:867)

private class UpgradeFrom108 extends BaseMigration {
        UpgradeFrom108() {
            super(108);
        }

        @Override
        public boolean migrate(DynamicRealm realm) {
            RealmSchema schema = realm.getSchema();

            RealmObjectSchema imageSchema = schema.create("Image")
                    .addField("url", String.class)
                    .addField("alt_text", String.class);
            imageSchema.setEmbedded(true);

            RealmObjectSchema basicContentSchema = schema.create("BasicContent")
                    .addField("title", String.class)
                    .addField("target_url", String.class)
                    .addRealmObjectField("image", imageSchema);
            basicContentSchema.setEmbedded(true);

            RealmObjectSchema variantSchema = Objects.requireNonNull(schema.get("Variant"));
            RealmObjectSchema contentStreamCardSchema = schema.create("ContentStreamCard")
                    .addField("analytics_event", String.class)
                    .addField("display_priority", int.class)
                    .addField("style", int.class)
                    .addField("title", String.class)
                    .addRealmObjectField("basic_content", basicContentSchema)
                    .addRealmObjectField("variant", variantSchema)
                    .addField("content_type", int.class);
            contentStreamCardSchema.setEmbedded(true);

            RealmObjectSchema contentStreamContainerSchema = schema.create("ContentStreamContainer")
                    .addField("id", String.class)
                    .setRequired("id", true)
                    .addField("display_priority", int.class)
                    .addRealmListField("children", contentStreamCardSchema);
            contentStreamContainerSchema.setEmbedded(true);

            schema.create("ContentStream")
                    .addField("id", String.class)
                    .setRequired("id", true)
                    .addPrimaryKey("id")
                    .addRealmListField("containers", contentStreamContainerSchema)
                    .addField("retain", boolean.class);
            return true;
        }
    }

@RealmClass(embedded = true)
open class Image : RealmObject() {
    @JvmField var url: String? = null
    @JvmField var alt_text: String? = null
}

@RealmClass(embedded = true)
open class BasicContent : RealmObject() {
    @JvmField var body: String? = null
    @JvmField var target_url: String? = null
    @JvmField var image: Image? = null
}

// ... and so forth.