code: public Observable<ServiceResponse<DatabasePrincipalListResultInner>> addPrincipalsWithServiceResponseAsync(String resourceGroupName, String clusterName, String databaseName, List<DatabasePrincipalInner> value) {
          if (resourceGroupName == null) {
              throw new IllegalArgumentException("Parameter resourceGroupName is required and cannot be null.");
          }
          if (clusterName == null) {
              throw new IllegalArgumentException("Parameter clusterName is required and cannot be null.");
          }
          if (databaseName == null) {
              throw new IllegalArgumentException("Parameter databaseName is required and cannot be null.");
          }
          if (this.client.subscriptionId() == null) {
              throw new IllegalArgumentException("Parameter this.client.subscriptionId() is required and cannot be null.");
          }
          if (this.client.apiVersion() == null) {
              throw new IllegalArgumentException("Parameter this.client.apiVersion() is required and cannot be null.");
          }
          Validator.validate(value);
          DatabasePrincipalListRequest databasePrincipalsToAdd = new DatabasePrincipalListRequest();
          databasePrincipalsToAdd.withValue(value);
          return service.addPrincipals(resourceGroupName, clusterName, databaseName, this.client.subscriptionId(), this.client.apiVersion(), this.client.acceptLanguage(), databasePrincipalsToAdd, this.client.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<DatabasePrincipalListResultInner>>>() {
                  @Override
                  public Observable<ServiceResponse<DatabasePrincipalListResultInner>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<DatabasePrincipalListResultInner> clientResponse = addPrincipalsDelegate(response);
                          return Observable.just(clientResponse);
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: Add Database principals permissions.
  
  @param resourceGroupName The name of the resource group containing the Kusto cluster.
  @param clusterName The name of the Kusto cluster.
  @param databaseName The name of the database in the Kusto cluster.
  @param value The list of Kusto database principals.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the DatabasePrincipalListResultInner object