static void InPackets(IntPtr clientData, int numberBytes, int numberPackets, IntPtr inputData, IntPtr packetDescriptions)
{
GCHandle handle = GCHandle.FromIntPtr(clientData);
var afs = handle.Target as AudioFileStream;
var desc = AudioFile.PacketDescriptionFrom(numberPackets, packetDescriptions);
afs.OnPacketDecoded(numberBytes, inputData, desc);
}