code: public Observable<OutputInner> updateAsync(String resourceGroupName, String jobName, String outputName, OutputInner output, String ifMatch) {
          return updateWithServiceResponseAsync(resourceGroupName, jobName, outputName, output, ifMatch).map(new Func1<ServiceResponseWithHeaders<OutputInner, OutputsUpdateHeaders>, OutputInner>() {
              @Override
              public OutputInner call(ServiceResponseWithHeaders<OutputInner, OutputsUpdateHeaders> response) {
                  return response.body();
              }
          });
      }
docs: Updates an existing output under an existing streaming job. This can be used to partially update (ie. update one or two properties) an output without affecting the rest the job or output definition.
  
  @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 outputName The name of the output.
  @param output An Output object. The properties specified here will overwrite the corresponding properties in the existing output (ie. Those properties will be updated). Any properties that are set to null here will mean that the corresponding property in the existing output will remain the same and not change as a result of this PATCH operation.
  @param ifMatch The ETag of the output. Omit this value to always overwrite the current output. Specify the last-seen ETag value to prevent accidentally overwritting concurrent changes.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the OutputInner object