Get ping to player

The server instantiates and spawns a _player prefab_ for every player that joins the server. The code is centered around that prefab. How can I get the ping to that _player prefab_? I see in the [Network.GetAveragePing](http://unity3d.com/support/documentation/ScriptReference/Network.GetAveragePing.html) documentation that you need the reference to the _NetworkPlayer_, but I don't know how to get that from the _player prefab_