Add an option to process files in parallel with worker processes

[walkerburgin]

It looks like @swc/cli processes files in parallel on the main thread (here). It should be significantly faster to process files using a pool of worker sub-processes. This is straightforward to implement using @swc/core, but it would be really nice to be able to integrate the official CLI into our build system instead of this little custom wrapper.

I tried this out for minification on a large internal project with ~2400 output files:

• Running the CLI with --sync takes ~3m24s
• Running the CLI in parallel mode takes ~2m28s
• Using a pool of 8 worker processes takes ~18s

Is this something the project would consider?

[kdy1]

Yes, of course