Description of the feature request:

Currently, when building with --remote_download_toplevel, outputs of toplevel targets / aspects are only guaranteed downloaded before the build command exits.

However, the consumers of BEP, e.g. IDE, may listen to TargetComplete event from BEP and expect outputs are ready to be processed when the event is fired.

What underlying problem are you trying to solve with this feature?

We should wait for the downloads before sending TargetComplete event to not break the expectations for consumers of BEP.

Which operating system are you running Bazel on?

No response

What is the output of bazel info release?

No response

If bazel info release returns development version or (@non-git), tell us how you built Bazel.

No response

What's the output of git remote get-url origin; git rev-parse master; git rev-parse HEAD ?

No response

Have you found anything relevant by searching the web?

No response

Any other information, logs, or outputs that you want to share?

#6862
b/273514526