Extrinsic 2554-1

{
  "heartbeat": {
    "blockNumber": 2553,
    "sessionIndex": 42,
    "validatorsLen": 4,
    "authorityIndex": 0
  },
  "signature": "0x8ea186259724fdac5d77a3f4a51bb9a3f9c0847c6f15f961d697547477e5f202b4e0ef08a45153901551ae6c9e5fc2505297a3b28c711599b73d4586a7235085"
}