Progress.stderr
The next chunk of stderr that bazel produced since the last progress event or the beginning of the build. Consumers that need to reason about the relative order of stdout and stderr can assume that stderr has been emitted before stdout if both are present, on a best-effort basis.
Progress.stdout
The next chunk of stdout that bazel produced since the last progress event or the beginning of the build. Consumers that need to reason about the relative order of stdout and stderr can assume that stderr has been emitted before stdout if both are present, on a best-effort basis.

