int32 AddVariable ( const [FNiagaraVariable](API\Plugins\Niagara\FNiagaraVariable) & InVar, const [FNiagaraVariable](API\Plugins\Niagara\FNiagaraVariable) & InAliasedVar, [FName](API\Runtime\Core\UObject\FName) ModuleName, const [FPin](API\Plugins\NiagaraEditor\TNiagaraParameterMapHistory\FPin) * InPin, [TOptional](API\Runtime\Core\IO\TOptional)< [FNiagaraVariableMetaData](API\Plugins\Niagara\FNiagaraVariableMetaData) > InMetaData )