Extrinsic 1299-1

{
  "heartbeat": {
    "blockNumber": 1298,
    "sessionIndex": 21,
    "validatorsLen": 1,
    "authorityIndex": 0
  },
  "signature": "0x661d57d5d25ff761bebb630a0314b5ba760969e354443b3ce06e118a1931a2213c8b1786708edc01311b218785a64348a96638c14636a0d6e97097c84d5b6e88"
}