Does halide support RVar async?

[mym2009]

I want to execute compute and write memory concurrently:

x_idx(x, y) = calculate1(input, x, y);
y_idx(x, y) = calculate2(intput, x, y);
using halide, calcuating x_idx and y_idx spends 4ms.

for(int i = 0; i < input.height(); i++)
for(int j = 0; j < intput.width();j++)
output(x_idx(i,j), y_idx(i,j)) = input(i, j);
using c code, spend 10ms, cannot use multithread.
The equivalent halide code below:
RDom r(0, input.width(), 0, input.height());
output(x_idx(r.x, r.y), y_idx(r.x, r.y)) = input(r.x, r.y);
To write memory as soon as compute 4 pixel(neon 128), can I schedule RVar using async like this x_idx.store_root().compute_at(output, x).async?
Expect you reply. Thanks！