Comment 1 for bug 1047309

A first draft fix would say "if we have sent 0 bytes after X tries, fail". Looking at the man page, send() should block until the bytes requested are sent, or give other sorts of errors about the message size being too big, etc.

I would probably do something like:

num_zero_sends = 0
max_zero_sends = 3 # config entry?

while sent_bytes < ...:
  if sent == 0:
    num_zero_sends += 1
    if num_zero_sends > max_zero_sends:
        raise errors.ConnectionReset(...)
  else:
    num_zero_sends = 0

That allows us to have a transient '0' bytes sent at any point, but in the end
we must get forward progress or we will fail properly.