Adds or replaces tags on the context already in force, for every charge made in
it from now on — including by work it has already started, which shares that
context. For a tag only known partway through: a host that tags each request as it
arrives learns what the request was about (the file it uploaded, say) only once
the request has been read. Outside any runWithUsageTags it does nothing, and a
context nested inside this one keeps the tags it copied when it began.
Adds or replaces tags on the context already in force, for every charge made in it from now on — including by work it has already started, which shares that context. For a tag only known partway through: a host that tags each request as it arrives learns what the request was about (the file it uploaded, say) only once the request has been read. Outside any
runWithUsageTagsit does nothing, and a context nested inside this one keeps the tags it copied when it began.