The AvatarMixer used to completely parse incoming AvatarData update packets, store the results into the data members of an AvatarData instance, and then write the data member data to a fresh QByteArray whenever it needed to be copied to an outgoing packet.

Now all it does is verify for packet's format (in numBytesOfAvatarData()), pulls the position out (which it uses for proximity based prioritization) and then copies the data directly to a buffer.  When packing outgoing messages it just copies the buffer into the packet.