private async Task <CacheItem> GetCacheItemFromDatabaseAsync(string key)
{
var connectionSettings = new Nest.ConnectionSettings(new Uri(_uri)).DefaultMappingFor <CacheItem>(m => m.IndexName(_indexName));
var client = new Nest.ElasticClient(connectionSettings);
var response = await client.GetAsync <CacheItem>(new Nest.DocumentPath <CacheItem>(key));
return(response.Source);
}