@Override
                public OperationTracer getManagedTracer(final int txIndex, final Hash txHash) {
                  return OperationTracer.NO_TRACING;
                }
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