Extrinsic 2920-1

{
  "heartbeat": {
    "blockNumber": 2919,
    "sessionIndex": 48,
    "validatorsLen": 4,
    "authorityIndex": 2
  },
  "signature": "0x180f5eb00b26dc88722be988fd9b223398597ffd9d6d877960c91896d08798215f9276e6bacdb5e3630da86f6795675ce6fefbbd875867190683c78208606b82"
}