models/classes/runner/QtiRunnerService.php
public function storeTraceVariable(RunnerServiceContext $context, $itemUri, $variableIdentifier, $variableValue)
    {
        $this->assertQtiRunnerServiceContext($context);
        $metaVariable = $this->getTraceVariable($variableIdentifier, $variableValue);
        return $this->storeVariable($context, $itemUri, $metaVariable);
    }
public function storeTraceVariable(RunnerServiceContext $context, $itemUri, $variableIdentifier, $variableValue)
    {
        $this->assertQtiRunnerServiceContext($context);
        $metaVariable = $this->getTraceVariable($variableIdentifier, $variableValue);
        return $this->storeVariable($context, $itemUri, $metaVariable);
    }
Stores trace variable related to an item, a test or a section

@param RunnerServiceContext $context
@param $itemUri
@param $variableIdentifier
@param $variableValue
@return boolean
@throws \common_Exception