public async Task <Response <RouteTable> > GetAsync(string resourceGroupName, string routeTableName, string expand = null, CancellationToken cancellationToken = default)
        {
            if (resourceGroupName == null)
            {
                throw new ArgumentNullException(nameof(resourceGroupName));
            }
            if (routeTableName == null)
            {
                throw new ArgumentNullException(nameof(routeTableName));
            }

            using var message = CreateGetRequest(resourceGroupName, routeTableName, expand);
            await _pipeline.SendAsync(message, cancellationToken).ConfigureAwait(false);

            switch (message.Response.Status)
            {
            case 200:
            {
                RouteTable value = default;
                using var document = await JsonDocument.ParseAsync(message.Response.ContentStream, default, cancellationToken).ConfigureAwait(false);

                if (document.RootElement.ValueKind == JsonValueKind.Null)
                {
                    value = null;
                }
                else
                {
                    value = RouteTable.DeserializeRouteTable(document.RootElement);
                }
                return(Response.FromValue(value, message.Response));
            }