interface ILayerZeroMessagingLibrary {
    // send(), messages will be inflight.
    function send(address _userApplication, uint64 _lastNonce, uint16 _chainId, bytes calldata _destination, bytes calldata _payload, address payable refundAddress, address _zroPaymentAddress, bytes calldata _adapterParams) external payable;

    // estimate native fee at the send side
    function estimateFees(uint16 _chainId, address _userApplication, bytes calldata _payload, bool _payInZRO, bytes calldata _adapterParam) external view returns (uint nativeFee, uint zroFee);

    //---------------------------------------------------------------------------
    // setConfig / getConfig are User Application (UA) functions to specify Oracle, Relayer, blockConfirmations, libraryVersion
    function setConfig(uint16 _chainId, address _userApplication, uint _configType, bytes calldata _config) external;

    function getConfig(uint16 _chainId, address _userApplication, uint _configType) external view returns (bytes memory);
}
function setConfig(uint16 _chainId, address _userApplication, uint _configType, bytes calldata _config) external;

//---------------------------------------------------------------------------
// setConfig / getConfig are User Application (UA) functions to specify Oracle, Relayer, blockConfirmations, libraryVersion