/// <inheritdoc /> public async Task <bool> StartHistoryObservationOfOutgoingTransactionsAsync(string address) { ValidateAddressIsNotEmpty(address); try { await _runner.RunWithRetriesAsync(() => _api.StartHistoryObservationOfOutgoingTransactionsAsync(address)); } catch (ErrorResponseException ex) when(ex.StatusCode == HttpStatusCode.Conflict) { return(false); } return(true); }