Event keys are not necessarily located in the beginning

[m-kus]

Any event field can be marked as #[key] in Cairo, in most cases those fields are the first ones.
Here is a counter example: https://sepolia.voyager.online/event/330906_31_0

Event ABI:

{
            "type": "event",
            "name": "hello::HelloStarknet::BalanceIncreased",
            "kind": "struct",
            "members": [
                {
                    "name": "amount",
                    "type": "core::felt252",
                    "kind": "data"
                },
                {
                    "name": "by",
                    "type": "core::starknet::contract_address::ContractAddress",
                    "kind": "key"
                }
            ]
},

The decoding will likely fail here

starknet-indexer/pkg/indexer/decode/decode.go

Line 76 in 03af5b1

parsed, err := abi.DecodeEventData(values, *event, contractAbi.Structs, contractAbi.Enums)