@Serializable
sealed interface Pet {
    val name: String
}

@Serializable
data class Dog(
    @Contextual
    @SerialName("_id")
    val id: ObjectId,
    override val name: String,
    val favoriteToy: String,
) : Pet

@Serializable
data class Cat(
    @Contextual
    @SerialName("_id")
    val id: ObjectId,
    override val name: String,
    val favoritePlace: String,
) : Pet

suspend fun main() {
    val winston = Dog(ObjectId(), "Winston", "Ball")

    val collection = MongoClient.create().getDatabase("test").getCollection<Pet>("Pet")
    collection.insertOne(winston)

    collection.withDocumentClass<Document>().find().first().also { println(it) }
    collection.withDocumentClass<Dog>().find().first().also { println(it) }
    collection.withDocumentClass<Pet>().find().first().also { println(it) }  // FAILS with a codec error:


Stack trace:
Exception in thread "main" org.bson.BsonInvalidOperationException: Reading field '_id' failed expected STRING type but found: OBJECT_ID.
	at org.bson.codecs.kotlinx.DefaultBsonDecoder.decodeString(BsonDecoder.kt:302)
	at kotlinx.serialization.encoding.AbstractDecoder.decodeStringElement(AbstractDecoder.kt:58)
	at kotlinx.serialization.internal.AbstractPolymorphicSerializer.deserialize(AbstractPolymorphicSerializer.kt:52)
	at org.bson.codecs.kotlinx.KotlinSerializerCodec.decode(KotlinSerializerCodec.kt:182)

}