import asyncio
import traceback
import logging

async def handle_echo(reader: asyncio.StreamReader,
                      writer: asyncio.StreamWriter):
    data = await reader.read(4096)
    logging.info('Server received: %r', data)
    writer.write(data)
    await writer.drain()
    #writer.transport.abort()
    writer.close()

async def main_coro(loop: asyncio.AbstractEventLoop):
    logging.basicConfig(level=logging.DEBUG)
    server = await asyncio.start_server(handle_echo, '127.0.0.1', 8890, loop=loop)
    reader, writer = await asyncio.open_connection('127.0.0.1', 8890, loop=loop)
    writer.write(b'Hello world!')
    logging.info('Client received: %r', await reader.read(4096))
    # writer.transport.abort()
    # writer.close()
    await asyncio.sleep(0.1)
    logging.info('Client received: %r', await reader.read(4096))

    logging.info('Client transport is_closing(): %r',
                 writer.transport.is_closing())

    # write() after close fails silently or raises warnings
    for _ in range(6):
        writer.write(b'Goodbye')
        logging.info('Client transport is_closing(): %r',
                     writer.transport.is_closing())

    # drain() after close raises ConnectionResetError
    try:
        await writer.drain()
    except Exception as e:
        traceback.print_exc()

    # write_eof() after close raises mysterious AttributeError
    try:
        writer.write_eof()
    except Exception as e:
        traceback.print_exc()

def main():
    loop = asyncio.get_event_loop()
    loop.set_debug(True)
    loop.run_until_complete(main_coro(loop))

if __name__ == '__main__':
    main()