Usage

While debugging (application is paused on a breakpoint for example), hover with the mouse over the byte[] variable name. Click the small drop-down arrow on the View widget. The default viewer is IEnummerable Visualizer, under it you should see MsgPack debugging tool. Select the MsgPack debugging tool (optionally set it to default so next time you can just click view instead of the drop-down).

After selecting the MsgPack debugging tool you can analyse the MsgPack encoded contents of the file.