Sets the .protocol property on the client side web socket to the value provided here, which should be one of the strings specified in the protocols parameter when requesting the web socket. This is intended for clients and servers to specify sub-protocols to use to communicate to each other.

If the client does not respond to this frame with a pong within the timeout specified, the connection is deemed unhealthy and is closed. The close and error event will be emitted.

The default is 120 seconds. Set to 0 to disable timeouts.