[boost] Will the boost::asio::streambuf keep in sequency order when ostream write to boost::asio::streambuf multiple time?

Subject: [boost] Will the boost::asio::streambuf keep in sequency order when ostream write to boost::asio::streambuf multiple time?
From: hh h (jupiter.hce_at_[hidden])
Date: 2018-12-08 06:59:56

Hi,

Are there any problems in following statements? The receiver works a
few minutes, then got wrong number in header field.

std::shared_ptr<boost::asio::streambuf> buffer =
std::make_shared<boost::asio::streambuf>();
std::ostream os(buffer.get());
os.write((char *) &sendHeader, sizeof(sendHeader));
os.write((char *) sb.data(), sb.size());
boost::asio::async_write(socket_, *buffer.get(), .....);

Thank you.

- JHH