code: public function index($document, $id=null, $index, $type, array $options = array()) {
  		$params = array( '_id' => $id, 
     					     '_index' => $index, 
  					     '_type' => $type);
  
  		foreach ($options as $key => $value) {
  			$params['_' . $key] = $value;
  		}
  
  		$operation = array(
  			array('index' => $params),
  			$document 
  		);
  		$this->operations[] = $operation;
  		return $this;
  	}
docs: Index a new document or update it if existing
  
  @param array $document
  @param mixed $id Optional
  @param string $index Index
  @param string $type Type
  @param array $options Allow sending query parameters to control indexing further
  _refresh_ *bool* If set to true, immediately refresh the shard after indexing
  @return \Elasticsearch\Bulk