pub fn build_darwinia_message_client(
    endpoint: &str,
    inbound_address: Address,
    outbound_address: Address,
    chain_message_committer_address: Address,
    lane_message_committer_address: Address,
    fee_market_address: Address,
    account: Address,
    private_key: Option<&str>,
    indexer: TheGraphLikeEth,
    gas_option: Options
) -> Result<DarwiniaMessageClient<FeeMarketRelayStrategy>>