Extrinsic 1305-1

{
  "heartbeat": {
    "blockNumber": 1302,
    "sessionIndex": 21,
    "validatorsLen": 4,
    "authorityIndex": 0
  },
  "signature": "0xfa86d71e670cae0b101b1d9b8a9e08e59b7583714572e6c9e9c8f0027543c94761dc2052d4e5cf5ccc6a22e8eba3e994b71a76254d92410ad6413424f42d1c84"
}