public async Task<TaskModel> GetTaskAsync(Guid taskId)
{
var client = new HttpClient();
client.DefaultRequestHeaders.Add(
"Authorization",
new Signature(this._subscriptionId, this._secretKey).ToString());
var response = await client.GetAsync(_uri + taskId.ToString());
response.EnsureSuccessStatusCode();
return await response.Content.ReadAsAsync<TaskModel>();
}