This has been fixed with bpo-44011 on main branch.

Output on main branch:

--------------------------------------------------------------------------
/workspaces/cpython/main.py:42: DeprecationWarning: There is no current event loop
  loop = asyncio.get_event_loop()
received 8192, total 8192
received 8192, total 16384
received 8192, total 24576
received 8192, total 32768
received 8192, total 40960
received 8192, total 49152
received 8192, total 57344
received 8192, total 65536
received 8192, total 73728
received 8192, total 81920
received 8192, total 90112
received 8192, total 98304
received 8192, total 106496
received 8192, total 114688
received 8192, total 122880
received 8192, total 131072
received 8192, total 139264
received 8192, total 147456
received 8192, total 155648
received 8192, total 163840
received 8192, total 172032
received 8192, total 180224
received 8192, total 188416
received 8192, total 196608
received 8192, total 204800
received 8192, total 212992
received 8192, total 221184
received 8192, total 229376
received 8192, total 237568
received 8192, total 245760
received 8192, total 253952
received 8192, total 262144
received 8192, total 270336
received 8192, total 278528
received 8192, total 286720
received 8192, total 294912
received 8192, total 303104
received 8192, total 311296
received 8192, total 319488
received 8192, total 327680
received 8192, total 335872
received 8192, total 344064
received 8192, total 352256
received 8192, total 360448
received 8192, total 368640
received 8192, total 376832
received 8192, total 385024
received 8192, total 393216
received 8192, total 401408
received 8192, total 409600
received 0, total 409600

------------------------------------------------------------------------

This can be closed now @asvetlov.