One step

{
    "srcVertices": [
        {
            "serviceName": "test",
            "columnName": "user_id",
            "id": %s
        }
    ],
    "steps": [
      [
        {
          "label": "friends",
          "direction": "out",
          "offset": 0,
          "limit": %d
        }
      ]
    ]
}