Extrinsic 18821-1

{
  "heartbeat": {
    "blockNumber": 18820,
    "sessionIndex": 313,
    "validatorsLen": 4,
    "authorityIndex": 2
  },
  "signature": "0x3410730315837cffb23ad082405c9ed094c53da842670f0a50099af2d14a7742e6ef61ad94ec1caf503cd3aed8510fae33bea86c69c916d86495ff87d1e8648e"
}