Extrinsic 2557-1

{
  "heartbeat": {
    "blockNumber": 2555,
    "sessionIndex": 42,
    "validatorsLen": 4,
    "authorityIndex": 3
  },
  "signature": "0x02eb8c5c38de9b2b0337a0484ec0b2e30a20e3b67dca73fa450d8e9049716a769a181ece99125ab767dca6b7bd4a76ccd5e6d9fdfa6e02079514df1af7bade8c"
}