Extrinsic 2558-1

{
  "heartbeat": {
    "blockNumber": 2557,
    "sessionIndex": 42,
    "validatorsLen": 1,
    "authorityIndex": 0
  },
  "signature": "0x0886ec7c5a4e6b83f4068b133666760b5b957ff7154a5876284f0926bc56aa45dbd8aca5167985e28d39cff96af49246263d9248d8a12461b4ea4e0fd420818d"
}