Error of sync with bitcoin-core regtest

[nemoRevers]

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  final String mnemonic = generateMnemonic();

  final DescriptorSecretKey secretKey = await (await DescriptorSecretKey.create(
    network: Network.Regtest,
    mnemonic: await Mnemonic.fromString(mnemonic),
  ))
      .derive(await DerivationPath.create(path: "m/49'/0'/0'"));

  final Descriptor descriptorExternal = await Descriptor.newBip49(
    secretKey: secretKey,
    network: Network.Regtest,
    keychain: KeychainKind.External,
  );

  final Descriptor descriptorInternal = await Descriptor.newBip49(
    secretKey: secretKey,
    network: Network.Regtest,
    keychain: KeychainKind.Internal,
  );

  final Wallet wallet = await Wallet.create(
    descriptor: descriptorExternal,
    changeDescriptor: descriptorInternal,
    network: Network.Regtest,
    databaseConfig: const DatabaseConfig.memory(),
  );

  final AddressInfo address =
      await wallet.getAddress(addressIndex: const AddressIndex.reset(index: 0));
  print(address.address);

  final Blockchain blockchain = await Blockchain.create(
    config: const BlockchainConfig.rpc(
      config: RpcConfig(
        url: 'http://127.0.0.1:18443',
        network: Network.Regtest,
        authUserPass: UserPass(
          username: "your_username",
          password: "your_password",
        ),
        walletName: 'bdk_flutter',
      ),
    ),
  );
  await wallet.sync(blockchain);
  await wallet.getBalance();
}

I catch error below on wallet.sync(...)

[VERBOSE-2:dart_vm_initializer.cc(41)] Unhandled Exception: Rpc(Transport(SocketError(Os { code: 35, kind: WouldBlock, message: "Resource temporarily unavailable" }))))
#0 Wallet.sync (package:bdk_flutter/src/root.dart:1200:7)

#1 main (package:bdk_flutter_test/main.dart:51:3)