Extrinsic 3880-1

{
  "heartbeat": {
    "blockNumber": 3879,
    "sessionIndex": 64,
    "validatorsLen": 4,
    "authorityIndex": 2
  },
  "signature": "0xe84abe436d5121fe5fc6ac4e26c3cc2a4c7fe8c46b7e2f8dceab08912b7a622ba58e33f57e36824d661c91a587545c164dc4ecf0a0e2464a28df11d46d5f9b8f"
}