code: public Observable<ServiceResponse<FunctionInner>> retrieveDefaultDefinitionWithServiceResponseAsync(String resourceGroupName, String jobName, String functionName) {
          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 (jobName == null) {
              throw new IllegalArgumentException("Parameter jobName is required and cannot be null.");
          }
          if (functionName == null) {
              throw new IllegalArgumentException("Parameter functionName is required and cannot be null.");
          }
          if (this.client.apiVersion() == null) {
              throw new IllegalArgumentException("Parameter this.client.apiVersion() is required and cannot be null.");
          }
          final FunctionRetrieveDefaultDefinitionParameters functionRetrieveDefaultDefinitionParameters = null;
          return service.retrieveDefaultDefinition(this.client.subscriptionId(), resourceGroupName, jobName, functionName, functionRetrieveDefaultDefinitionParameters, this.client.apiVersion(), this.client.acceptLanguage(), this.client.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<FunctionInner>>>() {
                  @Override
                  public Observable<ServiceResponse<FunctionInner>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<FunctionInner> clientResponse = retrieveDefaultDefinitionDelegate(response);
                          return Observable.just(clientResponse);
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: Retrieves the default definition of a function based on the parameters specified.
  
  @param resourceGroupName The name of the resource group that contains the resource. You can obtain this value from the Azure Resource Manager API or the portal.
  @param jobName The name of the streaming job.
  @param functionName The name of the function.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the FunctionInner object