[FString](API\Runtime\Core\Containers\FString) GenerateAttributeIndexHLSL ( const [FNiagaraDataInterfaceRWAttributeHelper](API\Plugins\Niagara\FNiagaraDataInterfaceRWAttribute-) & AttributeHelper, const [FNiagaraDataInterfaceGeneratedFunction](API\Plugins\NiagaraShader\FNiagaraDataInterfaceGeneratedFu-) & FunctionInfo )