disconnect abstract method
Closes the WebSocket connection.
Set the optional code
and reason
arguments
to send close information to the remote peer.
If they are omitted, the peer will see
No Status Rcvd (1005)
code with no reason,
indicates that no status code was provided even though one was expected.
https://developer.mozilla.org/en-US/docs/Web/API/CloseEvent/code
Implementation
FutureOr<void> disconnect(
[int? code = 1000, String? reason = 'NORMAL_CLOSURE']);