function fillZrxQuote(
    IERC20 zrxBuyTokenAddress,
    address payable zrxTo,
    bytes calldata zrxData,
    uint256 ethAmount
) internal returns (uint256, uint256) {
    uint256 originalERC20Balance = 0;
    if(!signifiesETHOrZero(address(zrxBuyTokenAddress))) {
        originalERC20Balance = zrxBuyTokenAddress.balanceOf(address(this));
    }
    uint256 originalETHBalance = address(this).balance;

    (bool success,) = zrxTo.call{value: ethAmount}(zrxData);
    require(success, "Swap::fillZrxQuote: Failed to fill quote");

    uint256 ethDelta = address(this).balance.subOrZero(originalETHBalance);
    uint256 erc20Delta;
    if(!signifiesETHOrZero(address(zrxBuyTokenAddress))) {
        erc20Delta = zrxBuyTokenAddress.balanceOf(address(this)).subOrZero(originalERC20Balance);
        require(erc20Delta > 0, "Swap::fillZrxQuote: Didn't receive bought token");
    } else {
        require(ethDelta > 0, "Swap::fillZrxQuote: Didn't receive bought ETH");
    }

    return (erc20Delta, ethDelta);
}
