Extrinsic 4000-2

{
  "heartbeat": {
    "blockNumber": 3998,
    "sessionIndex": 66,
    "validatorsLen": 4,
    "authorityIndex": 0
  },
  "signature": "0x369facbc72de75d81bb54b503f26a3848ed5dbe0c6469046cad47b1df806367dbde3fab3f8d53aa270198ff28e252b31049effc6374a8c1e36fd31f6b253ab82"
}