How to generate PDF output of powerbi embedded report

Looks like, soon that will be available as part of API (After Feb 2020).
https://docs.microsoft.com/en-us/power-platform-release-plan/2019wave2/business-intelligence/api-export-report-powerpoint-pdf-jpeg

Developers will be able to provide their users with the option to export their data in PowerPoint, PDF, and JPEG formats in two main scenarios:

Interactive mode: End users interact with a report and export their own view of the data.
Non-interactive mode: Offline generation of snapshots distributed to different people in the organization.

The following capabilities will be supported:

Export report for both Power BI and non-Power BI users (SaaS and PaaS embed scenarios)
Export user context (the screenshot will include applied filters, cross filters, etc.)
Export including row-Level security (RLS)
Export a single page or entire report