public NavigableMap<Bytes32, Bytes> streamAccountFlatDatabase(
      final SegmentedKeyValueStorage storage,
      final Bytes startKeyHash,
      final Predicate<Pair<Bytes32, Bytes>> takeWhile) {

    return toNavigableMap(accountsToPairStream(storage, startKeyHash).takeWhile(takeWhile));
  }
This class represents a FlatDbReaderStrategy, which is responsible for reading and writing data
from flat databases. It implements various methods for storing and retrieving account data, code
data, and storage data from the corresponding KeyValueStorage.
ethereum/core/src/main/java/org/hyperledger/besu/ethereum/trie/pathbased/common/storage/flat/FlatDbStrategy.java