Playblast with Arnold


In Maya 2018 there is a new ability to render using Arnold directly within the main viewport just like you would do with say Viewport 2.0.
I want to utilize this ability in order to perform a playblast in order to directly generate an avi of a short animation sequence without going through render sequences.

This works in principle but there is an issue. The playblast mechanism is advancing the frames based on evaluation of the scene graph, however it seems to be unaware of the rendering process that Arnold is performing, so it moves to the next frame too early and the result is a video with partly rendered frames.

Can I tell playblast or Maya somehow to hold on before moving to the next frame until Arnold finishes rendering the current frame in the main viewport?

Hopefully there is a simple setting that can be done but I am open to more complicated solutions that involves Maya programming (API C++, MEL etc.).