Always yield Server.handle_comm coroutine
Without this change, I see the following when running [this](https://github.com/TomAugspurger/dask-perf/blob/master/bench_comm.py)
comm benchmark.
```
(ucx-dev) an.taugspurger@dgx05:~/ucx-dev-env/dask-perf$ python bench_comm.py
/home/nfs/an.taugspurger/ucx-dev-env/distributed/distributed/comm/tcp.py:436: RuntimeWarning: coroutine 'server_handle_comm' was never awaited
self.comm_handler(comm)
```
@@ -27,7 +27,7 @@ from .registry import Backend, backends
from .addressing import parse_host_port, unparse_host_port
from .core import Comm, Connector, Listener, CommClosedError, FatalCommClosedError
from .utils import (to_frames, from_frames,
- get_tcp_server_address, ensure_concrete_host)
+ get_tcp_server_address, ensure_concrete_host,)
logger = logging.getLogger(__name__)
@@ -433,7 +433,7 @@ class BaseTCPListener(Listener, RequireEncryptionMixin):
address, self.contact_address)
local_address = self.prefix + get_stream_address(stream)
comm = self.comm_class(stream, local_address, address, self.deserialize)
- self.comm_handler(comm)
+ yield self.comm_handler(comm)
def get_host_port(self):
"""
