// Called in IO thread.
size_t SslConnector::encode(char* buffer, size_t size)
{
    framing::Buffer out(buffer, size);
    size_t bytesWritten(0);
    {
        Mutex::ScopedLock l(lock);
        while (!frames.empty() && out.available() >= frames.front().encodedSize() ) {
            frames.front().encode(out);
            QPID_LOG(trace, "SENT [" << identifier << "]: " << frames.front());
            frames.pop_front();
            if (lastEof) --lastEof;
        }
        bytesWritten = size - out.available();
        currentSize -= bytesWritten;
    }
    if (bounds) bounds->reduce(bytesWritten);
    return bytesWritten;
}