Extrinsic 3400-1

{
  "heartbeat": {
    "blockNumber": 3398,
    "sessionIndex": 56,
    "validatorsLen": 4,
    "authorityIndex": 3
  },
  "signature": "0x0a996b9ec8a40e5adab4708f7923c70e3e983be6528aaa6bdb7fca41a4d7043ed403bec91b93155a6a332d1a0915e8c94067673e44641e3b4beb2ff6f217258f"
}