• Sum network_fee + rpc_fee + additional_fee into a single OS bigint.

    The fee is read from the node's confirm response. Two shapes are handled:

    • gas_operation.fees — the node's authoritative gas operation, when the node populates it (post-fork gas-separation model), preferred; else
    • transaction.content.transaction_fee — the fee carried on the confirmed transaction itself, which live nodes return with gas_operation: null.

    Returns 0n when neither is present (fee not exposed at confirm time).

    Parameters

    Returns bigint