Extrinsic 6520-1

{
  "heartbeat": {
    "blockNumber": 6518,
    "sessionIndex": 108,
    "validatorsLen": 4,
    "authorityIndex": 0
  },
  "signature": "0x58686ce384a433e7e88da61bdad8745a6b7232d33b77bd9a99a97ab1ba0155359e6435d08fdd22053bf13f918262c282427053db256603e4b133b6980c19c988"
}