new_contents: import asyncio
  import aiozmq
  import zmq
  import argparse
  import time
  
  
  def main():
      ap = argparse.ArgumentParser()
      ap.add_argument('--addr', default='tcp://127.0.0.1:7777',
                      help="Address to use, default `%(default)s`")
      gr = ap.add_mutually_exclusive_group()
      gr.add_argument('--sync', action='store_const', dest='mode',
                      const=sync_main, default=None,
                      help="Run synchronous example")
      gr.add_argument('--async', action='store_const', dest='mode',
                      const=async_main,
                      help="Run asynchronous example")
  
      ap.add_argument('--client', action='store_true', default=False,
                      help="Run client part")
      ap.add_argument('--server', action='store_true', default=False,
                      help="Run server part")
  
      options = ap.parse_args()
      return options.mode(options)
  
  
  def read_data():
      return input("Enter some phrase: ").encode('utf-8').split()
  
  
  def sync_main(options):
      print("Running sync at {!r}".format(options.addr))
  
      ctx = zmq.Context()
      srv_sock = cl_sock = None
      if options.server:
          srv_sock = ctx.socket(zmq.ROUTER)
          srv_sock.bind(options.addr)
  
      if options.client:
          cl_sock = ctx.socket(zmq.DEALER)
          cl_sock.connect(options.addr)
          data = read_data()
          cl_sock.send_multipart(data)
          print("Sync client write: {!r}".format(data))
  
      while True:
          if srv_sock:
              try:
                  data = srv_sock.recv_multipart(zmq.NOBLOCK)
                  print("Sync server read: {!r}".format(data))
                  srv_sock.send_multipart(data)
                  print("Sync server write: {!r}".format(data))
              except zmq.ZMQError:
                  pass
          if cl_sock:
              try:
                  data = cl_sock.recv_multipart(zmq.NOBLOCK)
                  print("Sync client read: {!r}".format(data))
                  return
              except zmq.ZMQError:
                  pass
          time.sleep(.1)
  
  
  def async_main(options):
      print("Running async at {!r}".format(options.addr))
      loop = asyncio.get_event_loop()
  
      stop = asyncio.Future()
  
      @asyncio.coroutine
      def server():
          router = yield from aiozmq.create_zmq_stream(
              zmq.ROUTER, bind=options.addr)
          while True:
              try:
                  data = yield from router.read()
              except asyncio.CancelledError:
                  break
              print("Async server read: {!r}".format(data))
              router.write(data)
              print("Async server write: {!r}".format(data))
          router.close()
  
      @asyncio.coroutine
      def client():
          dealer = yield from aiozmq.create_zmq_stream(
              zmq.DEALER, connect=options.addr)
          data = read_data()
          dealer.write(data)
          print("Async client write: {!r}".format(data))
          echo = yield from dealer.read()
          print("Async client read: {!r}".format(echo))
          stop.set_result(None)
  
      tasks = []
      if options.server:
          tasks.append(asyncio.ensure_future(server()))
  
      if options.client:
          tasks.append(asyncio.ensure_future(client()))
  
      if tasks:
          try:
              loop.run_until_complete(stop)
          except KeyboardInterrupt:
              loop.call_soon(loop.stop)
              loop.run_forever()
              loop.close()
  
  
  if __name__ == '__main__':
      main()
  
subject: add simple sync-async example