Swamp platform slime farm

A swamp slime farm that needs no slime chunk at all. The spawning platform sits in a swamp between Y51 and Y69, which is the only band swamp slimes use, and everything around it is spawnproofed with slabs and brown mushrooms so nothing else takes the spawns. An iron golem in the middle pulls the slimes across the platform, they walk onto magma blocks and die, hoppers under the floor feed a double chest, and you AFK on a scaffolding tower above it. No chunk hunting and no cave lighting to do. Swamp slimes only spawn in the dark, so the farm produces at night and the rate follows the moon phase, down to nothing on a new moon.

The spawning platform has to sit between Y51 and Y69. Kmond pinned that himself after the video went out, and it is what most of the "no slimes" reports come down to.
Do not miss a single mushroom. One gap lets a skeleton spawn and it shoots the iron golem, which Kmond says happened to him during testing.
Endermen open the same gap by stealing mushrooms, and they teleport inside the build.
angelahaggerty2749 lit the build with soul torches while working. The mushrooms still grow under them and nothing else spawns.
ghosterbeamng9599 uses 120 scaffolding for the AFK platform so the despawn sphere lines up with the farm.
ATmodDev raised the golem platform and the roof by 3 blocks because the slimes could not see the golem and would not come.