At SKALE we need to charge the exact cost of a particular transaction to a particular user.
The fundamental problem we need to solve is that at the very end of a Solidity transaction we need to find out exactly how much gas this transaction uses.
It turns out that simply measuring gas used as the last line in a Solidity function does not work, because there is some gas used and freed AFTER the last line when the function returns.
We would be happy to issue a token grant to someone who knows how to solve it.