Optional<Bytes32> getWithdrawalsRoot() {
    return header.getWithdrawalsRoot().map(Function.identity());
  }
Returns the withdrawals root of the current block.

@return an Optional containing the withdrawals root if it exists, otherwise an empty Optional
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/graphql/internal/pojoadapter/BlockAdapterBase.java