Extrinsic 878-1

{
  "heartbeat": {
    "blockNumber": 877,
    "sessionIndex": 14,
    "validatorsLen": 1,
    "authorityIndex": 0
  },
  "signature": "0x36b0c17f45c3ebfe9f40bb8e07a327a42d19238aa3cdfade05e9d259850c8236178e51b02695b2dd9cdce549ac134aa566d7144933f448ec1ae266ec5157bb8d"
}