CqlSharp.CqlConnection.OpenAsync C# (CSharp) Метод

        public override Task OpenAsync(CancellationToken cancellationToken)
        {
            if(State != ConnectionState.Closed)
                throw new InvalidOperationException("Connection must be closed before it is opened");

            return OpenAsyncInternal(cancellationToken);
        }

		public async Task<List<string>> Get(string appId, string itemId, string relation, string userId)
		{
			using (var conn = new CqlConnection(_connString))
			{
				await conn.OpenAsync().ConfigureAwait(false);
				var query = string.Format(
					System.Globalization.CultureInfo.InvariantCulture,
					"select values from negrapi.relations where app_id = '{0}' and item_id='{1}' and relation='{2}';",
					appId,
					GetKey(itemId, userId),
					relation);

				var cmd = new CqlCommand(
					conn,
					query,
					CqlConsistency.One);

				var result = await cmd.ExecuteScalarAsync().ConfigureAwait(false) as string;

				if (string.IsNullOrEmpty(result))
				{
					return null;
				}

				var list = JsonConvert.DeserializeObject<List<RecommendationsDataValue>>(result);
				return list
					.Select(i => i.ItemId)
					.ToList();
			}
		}