Call an async task function, and write a message to stderr
with an automatic spinner to show that weβre not blocked.
Note that generally the called function should not output
anything to stderr as this will interfere with the spinner.
Given a possibly tagged image like quay.io/foo/bar:latest and a digest 0ab32β¦, return
the digested form quay.io/foo/bar:latest@sha256:0ab32β¦
If the image already has a digest, it will be replaced.
Given an mount option string list like foo,bar=baz,something=else,ro parse it and find
the first entry like $optname=
This will not match a bare optname without an equals.