`write` hangs on a `Finished` `TlsStream`
when I use write on a TlsStream with state == Finished, the write hangs forever instead of popping an error:
https://github.com/status-im/nim-chronos/blob/6525f4ce1d1a7eba146e5f1a53f6f105077ae686/chronos/streams/asyncstream.nim#L783-L789
```nim
template checkStreamClosed*(t: untyped) =
  if t.state == AsyncStreamState.Closed: # "Finished" not handled
    raiseAsyncStreamUseClosedError()
```

Since `wstream.writerLoop` is not nil, it's added to the `wstream.queue`, except that the `tlsLoop` was exited once we reach the `Finished` state so it will never be completed

https://github.com/status-im/nim-chronos/blob/6525f4ce1d1a7eba146e5f1a53f6f105077ae686/chronos/streams/tlsstream.nim#L299-L301

EDIT: seems to be the same issue for state `Error`