Handler Example: use ERC-20 token to pay for gas

[rakita]

It is one of the interesting use cases where gas can be paid from ERC-20 account.

Handler that needs to be overwritten:

• deduct_caller from PreExecution: https://bluealloy.github.io/revm/crates/revm/handler.html#preexecutionhandler
• reimburse_caller and reward_beneficiary from post execution: https://bluealloy.github.io/revm/crates/revm/handler.html#postexecutionhandler
• validation check for Account here: validate_tx_against_state https://bluealloy.github.io/revm/crates/revm/handler.html#validationhandler.

[mahmudsudo]

can i take on this ?