balanceOf, etc, work as expected.
balanceOfworks as expected, except it is an
updatecall, which takes longer and consumes cycles.
transferis slow because it involves several canister calls.
shardTransfershould be used instead, which is called at the shard contract (and not the main contract).
transferFromwill always fail, since this token standard uses subscriptions (aka notifications), and not approvals, for inter-contract calls.
shardTransferAndCall(preferred) should be used instead.