Extrinsic 18639-1

{
  "heartbeat": {
    "blockNumber": 18638,
    "sessionIndex": 310,
    "validatorsLen": 1,
    "authorityIndex": 0
  },
  "signature": "0x16578798cb74a1b9503e88b92de5f90a30fa8dcf0a2ad6039690ed350a814239a548dc853be108320ecc81be97dc9ccefdaf39da2e48200777c405e5a0aa0d80"
}