parallel-function | Send yout Functions to a new Thread | Reactive Programming library

I'm developing a BI-LSTM model for sequence analysis using PyTorch. For which I am using torch.nn.LSTM. Using that module, you can have several layers with just passing a parameter num_layers to be the number of layers (e.g., num_layers=2). However all of them will have the same hidden_size which is partially fine for me, I just want to have all of them the same hidden_size but the last layer with a different size. Basic example follows:

I have some large shapefiles with multiple millions of polygons that I need to dissolve. Depending upon the shapefile I need to either dissolve by group or just use st_union for all. I have been using the st_par function and it has been working great for most sf applications. Though when I use this function on st_union it returns a list and I cannot figure out how to parallize the sf dissolve function st_union.

Any suggestions would be most helpful! Here is a small code snippet to illustrate my point.