Suggested common properties

[lejige]

Using recently the lib , I added the following properties in the source code which I found useful:

In SendReceiveExtension:

public static SendStatus SendMessage(this ZmqSocket socket, ZmqMessage message, TimeSpan frameTimeout)

We have a ReceiveMessage with frameTimeout but not a SendMessage.

In ZmqMessage :

    public void Append(Frame[] frames)

with the corresponding overload of

internal void AppendShallowCopy(Frame[] frames)

Just call NormalizeFrames one time at the end.

And the last one, as _frames is private readonly, and I dont want to create hundreds of ZmqMessage and Wrap/Unwrap are not that cool:

    public void Clear()
    {
        _frames.Clear();
    }