Description
All packets are sent reliable and ordered.
Delta compression is used to send only the difference between the last sent state and the current state.
For example if you synchronize a Transform. Scale x, y, z is most likely going to keep the same value.
Unity compares the state received by the client to the new state, if it is changed 1 bit and the data will be sent.
If it didn't change only a single bit will be sent.
When Unity detects that nothing has changed since the last state, no data will be sent at all.
Manual