code: public FunctionInner createOrReplace(String resourceGroupName, String jobName, String functionName, FunctionInner function) {
          return createOrReplaceWithServiceResponseAsync(resourceGroupName, jobName, functionName, function).toBlocking().single().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.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws CloudException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the FunctionInner object if successful.