title: tcpip 3-way handshake
body: <p>Why is data not transferred during the 3rd part of TCP 3-way handshake?
  e.g.</p>
  
  <p>(A to B)SYN</p>
  
  <p>(B to A)ACK+SYN</p>
  
  <p>(A to B) ACK.... why cant data be transferred along with this ACK?</p>