Extrinsic 20321-1

{
  "heartbeat": {
    "blockNumber": 20319,
    "sessionIndex": 338,
    "validatorsLen": 4,
    "authorityIndex": 0
  },
  "signature": "0x7e9cb826b7975e3c87ab639a9957a4860fe7097612d0d1ecbc328d150c760c38e35078d278afb9295b663577d4d74d70fe3c4fc18f851c02dad7fbb05f349e84"
}