void handle(final HttpServerRequest req, final Buffer body) {
    ObjectMapper objectMapper = JsonUtils.createObjectMapper();
    final ObjectReader t8nReader = objectMapper.reader();
    try {
      var t8nRequest = t8nReader.readTree(body.toString());
      JsonNode state = t8nRequest.get("state");
      JsonNode input = t8nRequest.get("input");

      if (state != null && input != null) {
        handleT8nRequest(req, objectMapper, state, input);
      } else {
        sendHelp(req, objectMapper);
      }
      req.response().send();
    } catch (JsonProcessingException e) {
      req.response().setStatusCode(500).end(e.getMessage());
    }
  }
Default constructor for the T8nServerSubCommand class. This constructor is required by PicoCLI
and assigns null to parentCommand.
ethereum/evmtool/src/main/java/org/hyperledger/besu/evmtool/T8nServerSubCommand.java