/// <summary>
        /// 
        /// </summary>
        /// <param name="customer"></param>
        /// <returns></returns>
        public async Task<Customer> AddAsync(Customer customer)
        {
            var requestUrl = string.Format(BaseUrl, this.StoreId);
            using (var client = CreateMailClient(requestUrl))
            {
                var response = await client.PostAsJsonAsync(string.Empty, customer).ConfigureAwait(false);
                await response.EnsureSuccessMailChimpAsync().ConfigureAwait(false);

                var customerResponse = await response.Content.ReadAsAsync<Customer>().ConfigureAwait(false);
                return customerResponse;
            }
        }
        /// <summary>
        /// The update async.
        /// </summary>
        /// <param name="storeId">
        /// The store id.
        /// </param>
        /// <param name="store">
        /// The store.
        /// </param>
        /// <returns>
        /// The <see cref="Task"/>.
        /// </returns>
        public async Task<Customer> UpdateAsync(string customerId, Customer customer)
        {
            var requestUrl = string.Format(BaseUrl, StoreId);
            using (var client = CreateMailClient(requestUrl + "/"))
            {
                var response = await client.PatchAsJsonAsync(customerId, customer).ConfigureAwait(false);
                await response.EnsureSuccessMailChimpAsync().ConfigureAwait(false);

                var customerResponse = await response.Content.ReadAsAsync<Customer>().ConfigureAwait(false);
                return customerResponse;
            }
        }