### What needs to get done Sped up the iterative design experience of using rockcraft. For example, this could be through more advanced caching between `rockcraft pack` calls. iiuc there is caching already (some things are preserved unless you do `rockcraft clean`), but it feels like the current state doesn't hit the right balance and more would be possible. As an example, if I am fixing a `RUN` directive in a dockerfile I can edit the file, rebuild, and likely docker starts building exactly where I left off last time due to caching (process takes a few seconds). The comparable experience in rockcraft is slower. Whether it is caching or something else that can improve this, something is missing. ### Why it needs to get done A lot of the development time spent using rocks is in rerunning `rockcraft pack` and waiting to see if you fixed whatever problem you're trying to solve.