Extrinsic 18509-1

{
  "heartbeat": {
    "blockNumber": 18508,
    "sessionIndex": 308,
    "validatorsLen": 4,
    "authorityIndex": 0
  },
  "signature": "0x3cafff7acbb4db619766a4970cd6a830816b553467c8e2bae7a21635866c75029ea955e3292adb9174630e00d71fd66bbd0d0f2f1dd7081edaace38d4627468e"
}