Make errAlreadyWroteClose exported

[Antonboom]

Hello!

I would like to get a mechanism to avoid unnecessary logging of the closing error:

	defer func() {
		err2 := wsConn.Close(websocket.StatusInternalError, "the sky is falling")
		if err2 != nil {
			logger.WithError(err2).Error("error on close websocket")
		}
	}()

Thanks.

[emersion]

Related: #286

[nhooyr]

Thanks for reporting @Antonboom.

Yes as @emersion pointed out please follow #286 as the tracking issue for this.

And apologies for the delayed response!