Serve own liquidity using @0x/asset-swapper

index.ts

const ownOrder: AssetSwapper.SignedOrder = {...}
const customBook = AssetSwapper.Orderbook.getOrderbookForProvidedOrders([
  ownOrder
]);
const quoter = new AssetSwapper.SwapQuoter(
  provider,
  customBook
);
const order = await quoter.getMarketBuySwapQuoteAsync(
  contractAddress,
  constants.WETH_ADDR,
  new AssetSwapper.BigNumber(amount).times(10 ** decimals)
);
const consumer = new AssetSwapper.SwapQuoteConsumer(provider);
const txId = await consumer.executeSwapQuoteOrThrowAsync(order, {
  useConsumerType: AssetSwapper.ConsumerType.Forwarder,
  feePercentage: constants.ZRX_FEE_PERCENTAGE,
  feeRecipient: constants.ZRX_FEE_RECIPIENT
});