When painting with the TerrainTools package installed, a swipe action across a Terrain object will result in very clear gaps of coverage in the painting action. If you do the same action with TerrainTools not installed, it results in a smoother brush stroke. There appears to be a noticable performance impact to the painting action when Terrain Tools is installed.

Repro Steps:
1. Create a Terrain Object
2. Paint Texture across the Terrain with a quick swipe across the Terrain
3. Install Terrain Tools develop
4. Paint Texture across the Terrain with a quick swipe across the Terrain

Actual Results:
The stroke with Terrain Tools not installed will be much smoother compared to with Terrain Tools installed

Expected Results:
Painting Performance would be the same when comparing Terrain Tools against the Built In Painting tools

Performance regression reproduced with the following Editor & Package Combinations:
2020.2.1f1 + TerrainTools 3.0.2-preview (develop)
2021.2.0a3 + TerrainTools 3.0.2-preview (released)

Has good performance on the follow Editors:
2020.2.1f1
2021.2.0a3