Intermittent issue on CatapultClient.Listen() when closing websocket

[avanaur]

Listen() seems to spawn a goroutine for reading websocket messages.

However, when the websocket is closed, the goroutine sometimes fails with this panic error.

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0xc8 pc=0xa44116]

goroutine 2753 [running]:
github.com/gorilla/websocket.(*Conn).NextReader(0x0, 0xc00000ed28, 0xc000419f40, 0x404de5, 0xc00053e420, 0xc000419f90)
        C:/Users/Tyrone/go/src/github.com/gorilla/websocket/conn.go:936 +0x26
github.com/gorilla/websocket.(*Conn).ReadMessage(0x0, 0xc000419f90, 0xc0003cac00, 0x331, 0x600, 0x0, 0x0)
        C:/Users/Tyrone/go/src/github.com/gorilla/websocket/conn.go:1026 +0x2f
github.com/proximax-storage/go-xpx-catapult-sdk/sdk/websocket.(*CatapultWebsocketClientImpl).Listen.func1(0xc000375900, 0xc00053e420)
        C:/Users/Tyrone/go/src/github.com/proximax-storage/go-xpx-catapult-sdk/sdk/websocket/client.go:132 +0x116
created by github.com/proximax-storage/go-xpx-catapult-sdk/sdk/websocket.(*CatapultWebsocketClientImpl).Listen
        C:/Users/Tyrone/go/src/github.com/proximax-storage/go-xpx-catapult-sdk/sdk/websocket/client.go:127 +0x98

My understanding is due to the setting of conn to nil as shown on the line below.

	for {
		select {
		case <-c.ctx.Done():
			if c.conn != nil {
				if err := c.conn.Close(); err != nil {
					panic(err)
				}
				c.conn = nil
			}
			return
		case msg := <-messagesChan:
			go c.messageRouter.RouteMessage(msg)
		}
	}

Can we remove the c.conn = nil to avoid panic?

For some reason, I can't replicate on a simple code the issue but on the app it always happens. The removal of above fixed my proble.