Create a lastGasUsed() function in Vm.sol

[AmadiMichael]

Component

Forge

Describe the feature you would like

With support for --isolate when running tests and scripts, it would be helpful to expose a function lastGasUsed() in VM.sol that returns the gasUsed of the immediate last top-level transaction.

Better still, a function gasUsed() returns (uint256[] memory) that returns an array of gasUsed of all top level calls made in that isolated vm execution

Additional context

This would be particularly helpful given that currently, when a function is called multiple times, the only way to see the gas used for individual calls is to look at the expanded trace, a gasUsed helper function, would make it possible for a dev to access and use this info how they deem fit.

No response

[mds1]

would make it possible for a dev to access and use this info how they deem fit.

Can you expand on the use case? Instead of a cheatcode specific to --isolate mode, a more generic solution may be to use forge test --gas-report, and perhaps update it to also output the raw data as JSON or something if needed