Extrinsic 18400-1

{
  "heartbeat": {
    "blockNumber": 18399,
    "sessionIndex": 306,
    "validatorsLen": 4,
    "authorityIndex": 1
  },
  "signature": "0xcc9f5184f562e45aebddf714383db84cbaed064e2e8c60bde3d5f4f8d0456572388d02c1aa1e8fcd17108757a8bb7fd20046dde4e4b38172c8bc41ed42bdd983"
}