by svinartchouk.alexis@free.fr:

There is something strange in the Send function (lines 287 to 301 in
websocket/websocket.go):

On the line 297 we have this:
w, err := ws.frameWriterFactory.NewFrameWriter(payloadType)
And on the next line, instead of checking the error, we directly write to w:
_, err = w.Write(data)
But if there was an error, w is nil and calling w.Write(data) leads to a runtime
exception.
Also, at the very beginning of the function, there is a check for the err variable which
have not been affected at this point.

Here is my corrected version:

func (cd Codec) Send(ws *Conn, v interface{}) (err error) {
    data, payloadType, err := cd.Marshal(v)
    if err != nil {
        return err
    }
    ws.wio.Lock()
    defer ws.wio.Unlock()
    w, err := ws.frameWriterFactory.NewFrameWriter(payloadType)
    if err != nil {
        return err
    }
    _, err = w.Write(data)
    w.Close()
    return err
}

Thanks