/// <summary> /// Gets all the user’s completed items (tasks). /// </summary> /// <param name="filter">The filter.</param> /// <returns>The completed items.</returns> /// <exception cref="HttpRequestException">API exception.</exception> /// <remarks>Only available for Todoist Premium users.</remarks> public Task <CompletedItemsInfo> GetCompletedAsync(ItemFilter filter = null) { var parameters = filter == null ? new List <KeyValuePair <string, string> >() : filter.ToParameters(); return(TodoistClient.PostAsync <CompletedItemsInfo>("completed/get_all", parameters)); }