public String getFieldName() {
      return fieldName;
    }
This class allows to filter a list of pending transactions

<p>Here is the list of fields that can be used to filter a transaction : from, to, gas, gasPrice,
value, nonce
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/results/transaction/pool/PendingTransactionFilter.java