Use Config.Filter to skip middleware

[frzi]

It seems like Config.Filter remained unused. One can now skip the websocket middleware if so desired. Returning false in the function means the middleware will be skipped and c.Next() will be called instead.

app.Use(websocket.New(func(c *websocket.Conn) {
	// Etc...
}, websocket.Config{
	Filter: func(c *fiber.Ctx) bool {
		return websocket.IsWebSocketUpgrade(c)
	},
}))