Send the native eosio.token to the contract with the memo stake:accountname and
it will stake all incoming tokens to the accountname specificed in the memo as CPU.
It doesn't transfer the stake, so it can be used as a cold storage account with auto staking to a hot wallet.
The account to which this contract is deployed needs the permission del with eosio.code delegation
and the linked auth: eosio::delegatebw. See https://wax-test.bloks.io/account/stakehub1111 on the WAX test net for example usage.
The contract also manages an allow list to limit auto bandwidth delegation to a few trusted users.
If the memo doesn't start with stake: the contract is basically a noop and won't reject the transfer.