After starting the client ([method connect_to_url]), you will need to [method MultiplayerPeer.poll] it at regular intervals (e.g. inside [method Node._process]).
Connects to the given URL requesting one of the given [code]protocols[/code] as sub-protocol. If the list empty (default), no sub-protocol will be requested.
If [code]true[/code] is passed as [code]gd_mp_api[/code], the client will behave like a network peer for the [MultiplayerAPI], connections to non-Godot servers will not work, and [signal data_received] will not be emitted.
If [code]false[/code] is passed instead (default), you must call [PacketPeer] functions ([code]put_packet[/code], [code]get_packet[/code], etc.) on the [WebSocketPeer] returned via [code]get_peer(1)[/code] and not on this object directly (e.g. [code]get_peer(1).put_packet(data)[/code]).
[b]Note:[/b] To avoid mixed content warnings or errors in HTML5, you may have to use a [code]url[/code] that starts with [code]wss://[/code] (secure) instead of [code]ws://[/code]. When doing so, make sure to use the fully qualified domain name that matches the one defined in the server's SSL certificate. Do not connect directly via the IP address for [code]wss://[/code] connections, as it won't match with the SSL certificate.
If specified, this [X509Certificate] will be the only one accepted when connecting to an SSL host. Any other certificate provided by the server will be regarded as invalid.
Emitted when the server requests a clean close. You should keep polling until you get a [signal connection_closed] signal to achieve the clean close. See [method WebSocketPeer.close] for more details.