code: public Observable<ServiceResponse<List<KeyVaultKeyInner>>> listKeyVaultKeysWithServiceResponseAsync(String resourceGroupName, String integrationAccountName, ListKeyVaultKeysDefinition listKeyVaultKeys) {
          if (this.client.subscriptionId() == null) {
              throw new IllegalArgumentException("Parameter this.client.subscriptionId() is required and cannot be null.");
          }
          if (resourceGroupName == null) {
              throw new IllegalArgumentException("Parameter resourceGroupName is required and cannot be null.");
          }
          if (integrationAccountName == null) {
              throw new IllegalArgumentException("Parameter integrationAccountName is required and cannot be null.");
          }
          if (this.client.apiVersion() == null) {
              throw new IllegalArgumentException("Parameter this.client.apiVersion() is required and cannot be null.");
          }
          if (listKeyVaultKeys == null) {
              throw new IllegalArgumentException("Parameter listKeyVaultKeys is required and cannot be null.");
          }
          Validator.validate(listKeyVaultKeys);
          return service.listKeyVaultKeys(this.client.subscriptionId(), resourceGroupName, integrationAccountName, this.client.apiVersion(), listKeyVaultKeys, this.client.acceptLanguage(), this.client.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<List<KeyVaultKeyInner>>>>() {
                  @Override
                  public Observable<ServiceResponse<List<KeyVaultKeyInner>>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<PageImpl2<KeyVaultKeyInner>> result = listKeyVaultKeysDelegate(response);
                          List<KeyVaultKeyInner> items = null;
                          if (result.body() != null) {
                              items = result.body().items();
                          }
                          ServiceResponse<List<KeyVaultKeyInner>> clientResponse = new ServiceResponse<List<KeyVaultKeyInner>>(items, result.response());
                          return Observable.just(clientResponse);
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: Gets the integration account's Key Vault keys.
  
  @param resourceGroupName The resource group name.
  @param integrationAccountName The integration account name.
  @param listKeyVaultKeys The key vault parameters.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the List&lt;KeyVaultKeyInner&gt; object