code: public Observable<FunctionInner> createOrReplaceAsync(String resourceGroupName, String jobName, String functionName, FunctionInner function, String ifMatch, String ifNoneMatch) {
          return createOrReplaceWithServiceResponseAsync(resourceGroupName, jobName, functionName, function, ifMatch, ifNoneMatch).map(new Func1<ServiceResponseWithHeaders<FunctionInner, FunctionsCreateOrReplaceHeaders>, FunctionInner>() {
              @Override
              public FunctionInner call(ServiceResponseWithHeaders<FunctionInner, FunctionsCreateOrReplaceHeaders> response) {
                  return response.body();
              }
          });
      }
docs: Creates a function or replaces an already existing function under an existing streaming job.
  
  @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.
  @param function The definition of the function that will be used to create a new function or replace the existing one under the streaming job.
  @param ifMatch The ETag of the function. Omit this value to always overwrite the current function. Specify the last-seen ETag value to prevent accidentally overwritting concurrent changes.
  @param ifNoneMatch Set to '*' to allow a new function to be created, but to prevent updating an existing function. Other values will result in a 412 Pre-condition Failed response.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the FunctionInner object