v1.4.beta10

What's Changed

• Preserve installables' state during apply_params_set() by @amaslenn in #643
• Control which env vars dumped for per-rand evaluation by @amaslenn in #642
• Align extra_env_vars definition in test and scenario by @amaslenn in #644
• Update USER_GUIDE.md by @TaekyungHeo in #646
• Add latency metric reporting for NCCL by @amaslenn in #645

Full Changelog: v1.4.beta9...v1.4.beta10