With this change, the full gas loop of a transaction can be tracked going from initial balance (`gasLimit`) back down to 0.
I validated on my regression test suite that those conditions applied to all transactions I have:
- First `OnGasConsumed` is always going from 0 -> `trx.gasLimit`
- Last `OnGasConsumed` "new value" is always 0
- trx.gasLimit - last balance of last `OnGasConsumed` is equal to `trx.gasUsed`
The addition of `reason` make it possible for a logger to filter out unwanted signal, for example one could want to drop all OpCode related gas change and only cares about "transaction" level. The reason is also a good thing for visibility and for creating powerful debug tools for Ethereum transaction execution.
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