How to use the web3-provider-engine/subproviders/web3.js function in web3-provider-engine

// static results
      this.engine.addProvider(new FixtureSubprovider({
        web3_clientVersion: 'ProviderEngine/v0.0.0/javascript',
        net_listening: true,
        eth_hashrate: '0x00',
        eth_mining: false,
        eth_syncing: true
      }));

      // filters
      this.engine.addProvider(new FilterSubprovider());

      // id mgmt
      this.engine.addProvider(new WalletSubprovider(wallet, {}));

      this.engine.addProvider(new Web3Subprovider(new Web3.providers.HttpProvider(rpcURL)));

      this.engine.on('block', function (block) {
        console.log('BLOCK CHANGED:', '#' + block.number.toString('hex'), '0x' + block.hash.toString('hex'));
      });

      // network connectivity error
      this.engine.on('error', function (err) {
        // report connectivity errors
        console.error(err.stack);
      });

      // start polling for blocks
      this.engine.start();
    }
    this.PasswordManagement = new PasswordManagement(this.localStorage);
    this.ContractInterface = new KeySplitContractInterface({ web3: this.web3, at: options.at, localStorage: this.localStorage });

// static results
      this.engine.addProvider(new FixtureSubprovider({
        web3_clientVersion: 'ProviderEngine/v0.0.0/javascript',
        net_listening: true,
        eth_hashrate: '0x00',
        eth_mining: false,
        eth_syncing: true,
      }))

      // filters
      this.engine.addProvider(new FilterSubprovider())

      // id mgmt
      this.engine.addProvider(new WalletSubprovider(wallet, {}))

      this.engine.addProvider(new Web3Subprovider(new Web3.providers.HttpProvider(rpcURL)));

      this.engine.on('block', function(block) {
        // We probably don't need to be spamming this to the console, but it's useful for debugging.
        console.log('BLOCK CHANGED:', '#'+block.number.toString('hex'), '0x'+block.hash.toString('hex'))
      })

      // network connectivity error
      this.engine.on('error', function(err){
        // report connectivity errors
        console.error(err.stack)
      });

      // start polling for blocks
      this.engine.start()
    }
    this.PasswordManagement = new PasswordManagement(this.localStorage);

var wallet_hdpath = "m/44'/60'/0'/0/";
var wallet = hdwallet.derivePath(wallet_hdpath + "0").getWallet();
var address = "0x" + wallet.getAddress().toString("hex");

console.log(address);

var providerUrl = "https://testnet.infura.io";
var testnet_engine = new ProviderEngine();
testnet_engine.addProvider(new WalletSubprovider(wallet, {}));
testnet_engine.addProvider(new Web3Subprovider(new Web3.providers.HttpProvider(providerUrl)));
testnet_engine.start(); // Required by the provider engine.

var providerUrl = "https://mainnet.infura.io";
var mainnet_engine = new ProviderEngine();
mainnet_engine.addProvider(new WalletSubprovider(wallet, {}));
mainnet_engine.addProvider(new Web3Subprovider(new Web3.providers.HttpProvider(providerUrl)));
mainnet_engine.start(); // Required by the provider engine.

module.exports = {
  migrations_directory: "./migrations",
  networks: {
    ropsten: {
      network_id: 3,    // Official ropsten network id
      provider: testnet_engine, // Use our custom provider
      from: address     // Use the address we derived
    },
    mainnet: {
      network_id: 1,    // Official mainnet network id
      provider: mainnet_engine, // Use our custom provider
      from: address,     // Use the address we derived
      //gasPrice: '0x13AB6680' , /// 33
      gasPrice: '0x2756CD00' , /// 66

export function nanoWeb3Provider(providerUrl, nanoPath) {
  const web3HttpProvider = new Web3.providers.HttpProvider(providerUrl);
  const engine = new ProviderEngine();

  engine.addProvider(new FilterSubprovider());
  engine.addProvider(LedgerWalletSubproviderFactory.default(new Web3(web3HttpProvider), nanoPath));
  engine.addProvider(new Web3Subprovider(web3HttpProvider));

  engine.on("block", () => {
    // console.log("================================");
    // console.log(
    //   "BLOCK CHANGED:",
    //   `#${block.number.toString("hex")}`,
    //   `0x${block.hash.toString("hex")}`
    // );
    // console.log("================================");
  });
  engine.start();
  engine.stop();

  return engine;
}

// Get the first account using the standard hd path.
var wallet_hdpath = "m/44'/60'/0'/0/";
var wallet = hdwallet.derivePath(wallet_hdpath + "0").getWallet();
var address = "0x" + wallet.getAddress().toString("hex");
console.log(address);

var providerUrl = "https://testnet.infura.io";
var testnet_engine = new ProviderEngine();
testnet_engine.addProvider(new WalletSubprovider(wallet, {}));
testnet_engine.addProvider(new Web3Subprovider(new Web3.providers.HttpProvider(providerUrl)));
testnet_engine.start(); // Required by the provider engine.

var providerUrl = "https://mainnet.infura.io";
var mainnet_engine = new ProviderEngine();
mainnet_engine.addProvider(new WalletSubprovider(wallet, {}));
mainnet_engine.addProvider(new Web3Subprovider(new Web3.providers.HttpProvider(providerUrl)));
mainnet_engine.start(); // Required by the provider engine.

module.exports = {
  migrations_directory: "./migrations",
  networks: {
    ropsten: {
      network_id: 3,    // Official ropsten network id
      provider: testnet_engine, // Use our custom provider
      from: address,     // Use the address we derived
      gasPrice: '0x2756CD00' , /// 66
      gasPrice: '0x3B023380' , /// 99
    },
    mainnet: {
      network_id: 1,    // Official mainnet network id
      provider: mainnet_engine, // Use our custom provider
      from: address,     // Use the address we derived

const Web3Subprovider = require("web3-provider-engine/subproviders/web3.js")
  const Web3 = require("web3")

  // Get our mnemonic and create an hdwallet
  let mnemonic = MNEMONIC
  let hdwallet = hdkey.fromMasterSeed(bip39.mnemonicToSeed(mnemonic))

  // Get the first account using the standard hd path.
  let wallet_hdpath = "m/44'/60'/0'/0/"
  let wallet = hdwallet.derivePath(wallet_hdpath + "0").getWallet()
  address = "0x" + wallet.getAddress().toString("hex")
  let providerUrl = "https://kovan.infura.io"
  engine = new ProviderEngine()
  engine.addProvider(new FilterSubprovider())
  engine.addProvider(new WalletSubprovider(wallet, {}))
  engine.addProvider(new Web3Subprovider(new Web3.providers.HttpProvider(providerUrl)))
  engine.start() // Required by the provider engine.
}

module.exports = {
  networks: {
    development: {
      host: 'localhost',
      port: 8545,
      network_id: '*',
    },
    kovan: {
      from: isTestnet ? address : null, // Use the address we derived
      gas:4900000,
      network_id: '42',
      provider: isTestnet ? engine : null, // Use our custom provider
    }

// Get our mnemonic and create an hdwallet
var mnemonic = "piano file obey immense polar rack great subject clutch camera maid ostrich";
var hdwallet = hdkey.fromMasterSeed(bip39.mnemonicToSeed(mnemonic));

// Get the first account using the standard hd path.
var wallet_hdpath = "m/44'/60'/0'/0/";
var wallet = hdwallet.derivePath(wallet_hdpath + "0").getWallet();
var address = "0x" + wallet.getAddress().toString("hex");

var providerUrl = "https://testnet.infura.io";
var engine = new ProviderEngine();
// filters
engine.addProvider(new FilterSubprovider());

engine.addProvider(new WalletSubprovider(wallet, {}));
engine.addProvider(new Web3Subprovider(new Web3.providers.HttpProvider(providerUrl)));
engine.start(); // Required by the provider engine.

module.exports = {
  networks: {
    ropsten: {
      network_id: 3,    // Official ropsten network id
      provider: engine, // Use the custom provider
      from: address,     // Use the address derived address
      gas: 4444444
    },
    development: {
      host: "localhost",
      port: 8545, // This is the conventional port. If you're using the Ganache Blockchain, change port value to the Ganache default port 7545. If you're using Truffle develop network, change port value to 9545
      network_id: "*", // Match any network id. You may need to replace * with your network Id
      from: "", // Add your unlocked account within the double quotes
      gas: 4444444

var EthForwarder = function (accounts, fdc) {
    this.accounts = accounts;
    this.fdc = fdc;
    if (ethProvider == null)
        ethProvider = new Web3.providers.HttpProvider(G.DEFAULT_ETHEREUM_NODE);
    
    var engine = new ProviderEngine.Engine();
    var wallet = Wallet.fromPrivateKey(EthJSUtil.toBuffer(accounts.ETH.priv))
    engine.addProvider(new WalletSubprovider(wallet, {}));
    engine.addProvider(new Web3Subprovider(ethProvider));
    engine.start(); // Required by the provider engine.
    FDC.setProvider(engine);
}

var providerUrl = "https://rinkeby.infura.io";
var testnet_engine = new ProviderEngine();
testnet_engine.addProvider(new WalletSubprovider(wallet, {}));
testnet_engine.addProvider(new Web3Subprovider(new Web3.providers.HttpProvider(providerUrl)));
testnet_engine.start(); // Required by the provider engine.

var providerUrl = "https://ropsten.infura.io";
var ropsten_engine = new ProviderEngine();
ropsten_engine.addProvider(new WalletSubprovider(wallet, {}));
ropsten_engine.addProvider(new Web3Subprovider(new Web3.providers.HttpProvider(providerUrl)));
ropsten_engine.start(); // Required by the provider engine.

var providerUrl = "https://mainnet.infura.io";
var mainnet_engine = new ProviderEngine();
mainnet_engine.addProvider(new WalletSubprovider(wallet, {}));
mainnet_engine.addProvider(new Web3Subprovider(new Web3.providers.HttpProvider(providerUrl)));
mainnet_engine.start(); // Required by the provider engine.

module.exports = {
  migrations_directory: "./migrations",
  networks: {
    ropsten: {
      network_id: 3,    // Official ropsten network id
      provider: ropsten_engine, // Use our custom provider
      from: address,     // Use the address we derived
      gasPrice: '0x2756CD00' , /// .66 gwei
      gasPrice: '0x24E160300' , /// 9.9 gwei
    },
    rinkeby: {
      network_id: 4,    // Official rinkeby network id
      provider: testnet_engine, // Use our custom provider
      from: address,     // Use the address we derived

export function multiWalletProvider(nodeUrl) {
  const web3HttpProvider = new Web3.providers.HttpProvider(nodeUrl);
  const engine = new ProviderEngine();

  const fas = getFixtureAccounts();
  const wallets = [];
  for (const name of Object.keys(fas)) {
    if (fas[name].privateKey !== null) {
      const privateKey = Buffer.from(fas[name].privateKey.substr(2), "hex");
      const wallet = new Wallet(privateKey);
      wallets.push(wallet);
    }
  }

  engine.addProvider(new MultiWalletSubprovider(wallets));
  engine.addProvider(new Web3Subprovider(web3HttpProvider));
  engine.start();
  engine.stop();

  return engine;
}