private async Task EnsureCollectionExists <T>(IArangoDatabase db)
{
if (!_ensuredCollectionExists)
{
_factory.AddCollectionNameMap <Document <T> >();
var(success, result) = await db.TryCreateCollectionAsync <Document <T> >();
if (!success)
{
throw new ArangoServerException(result);
}
_ensuredCollectionExists = true;
}
}