grouped output example

example.json

[
  {
    "id": "prometheus_test{PUT}",
    "data": [
      {
        "timestamp": 1482999784249,
        "value": 2
      },
      {
        "timestamp": 1482999874249,
        "value": 5
      },
      {
        "timestamp": 1482999964249,
        "value": 8
      }
    ]
  },
  {
    "id": "prometheus_test{GET}",
    "data": [
      {
        "timestamp": 1482999814249,
        "value": 3
      },
      {
        "timestamp": 1482999904249,
        "value": 6
      },
      {
        "timestamp": 1482999994249,
        "value": 9
      }
    ]
  },
  {
    "id": "prometheus_test{DELETE}",
    "data": [
      {
        "timestamp": 1482999844249,
        "value": 4
      },
      {
        "timestamp": 1482999934249,
        "value": 7
      }
    ]
  }
]