[boost] How to clean boost::asio::streambuf before writing to it?

Sorry, this is really a silly question, but I could not find a clear API in streambuf reference, I have following code to call PacketData in a loop, the buffer.get() looked to accumulate previous data in the buffer, so I should call buffer.clear() before calling buffer.get(), but apparently there no ‘clear’ in boost::asio::basic_streambuf. PacketData(const msgpack::sbuffer &sb, boost::asio::streambuf &buffer)) { ....... std::ostream os(buffer.get()); os.write((char *)&header, sizeof(header)); os.write((char *)sb.data(), sb.size()); ....... } Thank you. Kind regards, - jh -- "A man can fail many times, but he isn't a failure until he begins to blame somebody else." -- John Burroughs