Extrinsic 2559-1

{
  "heartbeat": {
    "blockNumber": 2558,
    "sessionIndex": 42,
    "validatorsLen": 1,
    "authorityIndex": 0
  },
  "signature": "0xea267cf998a0ff9a0300704a7893b3c57070d2fde0c423cdc2208de5d07d55790a165cf2d2d4dadb13038da76dec2c5b11b3c7c20975dc1ae2a88ccb5407ac84"
}