@Override
  public boolean equals(final Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    final TransactionTraceResult that = (TransactionTraceResult) o;
    return Objects.equals(txHash, that.txHash)
        && status == that.status
        && Objects.equals(errorMessage, that.errorMessage);
  }
Get an optional error message associated with the transaction trace.

@return An optional error message, which may be empty if no error occurred.
plugin-api/src/main/java/org/hyperledger/besu/plugin/data/TransactionTraceResult.java