Extrinsic 4420-1

{
  "heartbeat": {
    "blockNumber": 4419,
    "sessionIndex": 73,
    "validatorsLen": 4,
    "authorityIndex": 3
  },
  "signature": "0xa891d1dddd6a0545dfeb1ed053a33dd615a5ce52b212fa164b30cf5387b2d86091b239201e1c41906d03b44fce52e62c72297d949db5e9a82b9cf8ad7ed10d8d"
}