Often you want to create particles emitters with the particles already spawned and after one cycle.

This is useful in for example: it should be heavily snowing in the level. Without prewarming the level would always start without snow and only slowly have some snow falling. Or if you equip a torch it should already be fully burning and not slowly start to burn.

This would be fixed by prewarming (that's what Unity calls it or preprocess is what Godot calls it). This could be implemeted this way: if the toggle is set the particles update function is called in a for loop (for one cycle, or maybe for a duration given by the user) on created.

my current workaround is:
on created, set object timescale to a very high number, wait a fraction of a second and set object timescale back to 1.
While this works , this means you get some really weird looking particle start up or have to keep the particles hidden for a bit, which mean not having the particles available directly.

(this setting should only be available if the mode is set to spray as it doesn't make sense for one-off imo)