presto-main/src/main/java/io/prestosql/operator/PageSourceOperator.java/PageSourceOperator/PageSourceOperator
class PageSourceOperator:    public PageSourceOperator(ConnectorPageSource pageSource, OperatorContext operatorContext)
    {
        this.pageSource = requireNonNull(pageSource, "pageSource is null");
        this.operatorContext = requireNonNull(operatorContext, "operatorContext is null");
    }