Fragment `discard` vs. `COLOR.w = 0` vs. `COLOR.w = false`

Godot Version

4.2.1-stable (or later if relevant)

Question

for shaders which involves creating generative textures (like a a set of lines in a ruller), what is cheaper to render? setting COLOR.w to 0 or false, or invoking discard on a Fragment?

i want to do micro-optimizations too, so if there’s any nuances i should understand, i would appreciate it if you can include some info about that too ^^
thank you either way <3

It depends Shading language — Godot Engine (stable) documentation in English

Discard is quite expensive so if you can use transparency instead