The client sends:
                        {
  "jsonrpc": "2.0",
  "id": 4,
  "method": "GetProgress",
  "handle": -1,
  "params": [
    0
  ]
}
                        The engine returns:
                        {
  "jsonrpc": "2.0",
  "id": 4,
  "result": {
    "qProgressData": {
      "qStarted": true,
      "qFinished": true,
      "qCompleted": 0,
      "qTotal": 0,
      "qKB": 0,
      "qMillisecs": 0,
      "qPersistentProgress": "INLFED << INLC98 3 Lines fetched\n",
      "qErrorData": [],
      "qPersistentProgressMessages": [
        {
          "qMessageCode": 0,
          "qMessageParameters": [
            "INLFED << INLC98"
          ]
        },
        {
          "qMessageCode": 21,
          "qMessageParameters": [
            "3"
          ]
        }
      ],
      "qTransientProgressMessage": {
        "qMessageCode": 0,
        "qMessageParameters": [
          "3"
        ]
      }
    }
  }
}
                        Progress messages are returned. There is no error.