`foldxt` type unstable

[MasonProtter]

Filed in JuliaFolds/Transducers.jl#569 by @atbug

const grid = [[i, j] for i in -4:4, j in -4:4]

foldxt(+, Map(i -> grid[i]), 1:length(grid))

seems to be type unstable, while foldl works well.

I plan to fix this with https://github.com/MasonProtter/StableTasks.jl once it is registered

[leonardogalliano]

Any update? It seems to me that any call of foldxt is type unstable. Even the examples in https://juliafolds.github.io/Transducers.jl/dev/tutorials/tutorial_parallel/#tutorial-parallel

using Transducers

@code_warntype foldxt(+, Map(sin), rand(10_000_000))