Extrinsic 21440-1

{
  "heartbeat": {
    "blockNumber": 21438,
    "sessionIndex": 357,
    "validatorsLen": 4,
    "authorityIndex": 2
  },
  "signature": "0x766320e8f9376abc71e47b38ba98fb7db03d5616621e3f975196d227dce0673a056ad49f4866f89fb204cca7a044eb5d84a451868fe883b80674288b91f3e98b"
}