[ARCHITECTURE]Use the std::flush when sending an xpcc::flush
[ARCHITECTURE]Use the std::flush when sending an xpcc::flush

chrism333/xpcc,dergraaf/xpcc,chrism333/xpcc,dergraaf/xpcc,chrism333/xpcc,dergraaf/xpcc,dergraaf/xpcc,chrism333/xpcc