Extrinsic 279-1

{
  "heartbeat": {
    "blockNumber": 278,
    "sessionIndex": 4,
    "validatorsLen": 4,
    "authorityIndex": 2
  },
  "signature": "0x64a9b40545ebb8ea60d5f20d6034ca7bdd3a9c59eb8f84b8ff85fb0696664772b30ba9580f7b191aa604707fab406fd4ed863f7172c53227fbb84626774d8e87"
}