title: TCP send function retransmission logic?
body: <p>When we send a packet and re-transmission starts does we come out of send function or not?
  In my case my application took a lock and waits for send to return and then it leaves the lock.</p>
  
  <p>But In my scenario it never came back. I want to know do we really come out of send function when we have a re transmission case?</p>