Extrinsic 18555-1

{
  "heartbeat": {
    "blockNumber": 18554,
    "sessionIndex": 309,
    "validatorsLen": 4,
    "authorityIndex": 3
  },
  "signature": "0x5a9e30a60258d27dc63a971da1777402333059e58a32e474780e79ae5a0e4a4afbf70441d11ad3d01201448e7c26705555c2f8fef7fb30d11702805b5360a58d"
}