Extrinsic 18459-1

{
  "heartbeat": {
    "blockNumber": 18458,
    "sessionIndex": 307,
    "validatorsLen": 4,
    "authorityIndex": 0
  },
  "signature": "0x8eb549319297f9de94a521a52ddb8018a8dfe77e99f488910e4b572f2456ee61edd94c31664166683f9973698d382de0b1ff492b18746d0e353febdd99863b8e"
}