The Data Packet is a location in application storage where the physical mouse device driver returns to the caller the following data:
┌─────────────────────────────────────────┐ │Field Length C Datatype │ ├─────────────────────────────────────────┤ │Element Count WORD USHORT │ ├─────────────────────────────────────────┤ │Queue Size WORD USHORT │ └─────────────────────────────────────────┘