curl -X POST http://localhost:5080/api/v1/_kinesis_firehose \
  -H 'X-Amz-Firehose-Access-Key: <push_token>' \
  -H 'content-type: application/json' \
  -d '{"requestId":"req-1","timestamp":1790000000000,"records":[{"data":"eyJsZXZlbCI6ImluZm8ifQo="}]}'

{ "requestId": "req-1", "timestamp": 1790000000123 }