A UX technique, illustrated by early Instagram: start an expensive operation (photo upload) the instant the triggering action happens (the photo is taken) rather than waiting for the user to reach the nominal completion step (tapping Share). Instagram's team later revealed this — not any compression or engineering trick — was the real source of its famous upload-speed advantage, because roughly 95–99% of photos taken in the app get posted anyway.
Part of the implementation behind Instagram's 2010 Strategy (Performance + Delighter Case Study)'s performance advantage.
Apply: When most user actions eventually reach a wait-heavy end state, start the expensive operation optimistically at the earliest reliable signal and roll back only for the rare cancellation, rather than waiting for explicit confirmation.