@Override
                public OperationTracer getManagedTracer(final int txIndex, final Hash txHash)
                    throws Exception {
                  outDir.toFile().mkdirs();
                  var traceDest =
                      new FileOutputStream(
                          outDir
                              .resolve(
                                  String.format("trace-%d-%s.jsonl", txIndex, txHash.toHexString()))
                              .toFile());

                  var jsonTracer =
                      new StandardJsonTracer(
                          new PrintStream(traceDest),
                          parentCommand.showMemory,
                          !parentCommand.hideStack,
                          parentCommand.showReturnData,
                          parentCommand.showStorage,
                          parentCommand.eip3155strict);
                  outputStreams.put(jsonTracer, traceDest);
                  return jsonTracer;
                }
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