How to use packet canceller to steal items with no trace.

Everything else should be on except these.

Packet canceller packets to not cancel in S2C section :
InventoryS2CPacket
ChatSuggestionsS2CPacket
ChatMessageS2CPacket
OpenScreenS2CPacket

Packet canceller packets to not cancel in C2S section :
CommandExecutionC2SPacket
ClientCommandC2SPacket

Its a ghost item till you leave and rejoin. If you open the inv it synchronizes your inventory with the server, making the item into a real item again.