code: public ServiceFuture<String> getContentAsync(String resourceGroupName, String automationAccountName, String runbookName, final ServiceCallback<String> serviceCallback) {
          return ServiceFuture.fromResponse(getContentWithServiceResponseAsync(resourceGroupName, automationAccountName, runbookName), serviceCallback);
      }
docs: Retrieve the content of runbook identified by runbook name.
  
  @param resourceGroupName Name of an Azure Resource group.
  @param automationAccountName The name of the automation account.
  @param runbookName The runbook name.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object