How to update TriangleMesh geometry in Scene?

[anticdimi]

Checklist

• [X] I have searched for similar issues.
• [X] For Python issues, I have tested with the latest development wheel.
• [X] I have checked the release documentation and the latest documentation (for master branch).

My Question

Hi, I can't seem to find a way of updating geometry while using TriangleMesh? There is update_geometry method, but it only can take Pointcloud as input, and add_geometry can get slow if I only want to update the colors of several vertices...