code: public function createPayload() 
  	{
  		$payloads = array();
  		foreach ($this->operations as $operation) {
  			foreach ($operation as $partial) {
  				$payloads[] = json_encode($partial);
  			}
  		}
  		return join("\n", $payloads)."\n";
  	}
docs: create a request payload with all pending operations
  @return string