This is a quality of life improvement plugin aimed to make inventory management is OSRS a

little less annoying by predicting what the inventory will look like the next tick.

Or explained by someone who can write:

> Normally, most changes in your inventory apply on the next tick (as with most actions in the game). Instant inventory

> will cause them to render in your inventory giving visual feedback before they actually apply. For example, you drop a

> fish at the beginning of a tick. Normally it will take about 600 ms for the drop action to process and the item to

> disappear from your inventory. With instant inventory, it will disappear from your inventory immediately (600 ms

> sooner), but it won’t actually leave your inventory and hit the floor until the next tick when it normally would.