Should signal SM with EVENT_ERROR on error in write_to_net_io(), EVENT_EOS only signaled from read_from_net()

    if (!r || r == -ECONNRESET) {

  int64_t r = vc->load_buffer_and_write(towrite, buf, total_written, needs);

  if (total_written > 0) {
    NET_SUM_DYN_STAT(net_write_bytes_stat, total_written);
    s->vio.ndone += total_written;
  }

  // check for errors
  if (r <= 0) { // if the socket was not ready,add to WaitList
    if (r == -EAGAIN || r == -ENOTCONN) {
      NET_INCREMENT_DYN_STAT(net_calls_to_write_nodata_stat);
      if ((needs & EVENTIO_WRITE) == EVENTIO_WRITE) {
        vc->write.triggered = 0;
        nh->write_ready_list.remove(vc);
        write_reschedule(nh, vc);
      }
      if ((needs & EVENTIO_READ) == EVENTIO_READ) {
        vc->read.triggered = 0;
        nh->read_ready_list.remove(vc);
        read_reschedule(nh, vc);
      }
      return;
    }
    if (!r || r == -ECONNRESET) {
      vc->write.triggered = 0;
      write_signal_done(VC_EVENT_EOS, nh, vc);
      return;
    }
    vc->write.triggered = 0;
    write_signal_error(nh, vc, (int)-total_written);
    return;

257   /**
258     Initiates write. Thread-safe, may be called when not handling
259     an event from the NetVConnection, or the NetVConnection creation
260     callback.
261 
262     Callbacks: non-reentrant, c's lock taken during callbacks.
263 
264     <table>
265       <tr>
266         <td>c->handleEvent(VC_EVENT_WRITE_READY, vio)</td>
267         <td>signifies data has written from the reader or there are no bytes available for the reader to write.</td>
268       </tr>
269       <tr>
270         <td>c->handleEvent(VC_EVENT_WRITE_COMPLETE, vio)</td>
271         <td>signifies the amount of data indicated by nbytes has been read from the buffer</td>
272       </tr>
273       <tr>
274         <td>c->handleEvent(VC_EVENT_ERROR, vio)</td>
275         <td>signified that error occured during write.</td>
276       </tr>
277     </table>
278 
279     The vio returned during callbacks is the same as the one returned
280     by do_io_write(). The vio can be changed only during call backs
281     from the vconnection. The vconnection deallocates the reader
282     when it is destroyed.
283 
284     @param c continuation to be called back after (partial) write
285     @param nbytes no of bytes to write, if unknown msut be set to INT64_MAX
286     @param buf source of data
287     @param owner
288     @return vio pointer
289 
290   */
291   virtual VIO *do_io_write(Continuation *c, int64_t nbytes, IOBufferReader *buf, bool owner = false) = 0;

write_signal_done(VC_EVENT_EOS, nh, vc);