Just wanted to share my experience:
I was suffering with my elixir vscode devcontainer (docker) environment, because tests took ~20 seconds to start running.
I tried delegating the workspace:
This makes the shared folder (between the container and the host) to write first on the container and to be eventually consistent with the host, so it doesn’t try to sync all the time.
At the beginning it worked, but sometime at the beginning of this year (2021) slowed down again.
Finally got with this amazing post by Marcus Baguley, that recommends to change the /deps and /_build folder to somewhere outside the workspace folder:
And now it works as expected.
Totally recommended for your dev environment!