AFAIK INET is not make use of internal buffers propably you mean the buffer of the OS for this is responsible the OS and all you have to do is to "wait" for a while when you hit its limitsthis might help [ https://lnet.wordpress.com/usage/sockets-protocols-and-sending/ ]
So, which means you have to just simple loop reading out what is in the buffer until there is nothing in the buffer to be read. lol...