Check pool box rate in pool health assessment

[greenhat]

Close #296

[github-actions]

Pull Request Test Coverage Report for Build 5419792705

• 0 of 7 (0.0%) changed or added relevant lines in 3 files are covered.
• 2 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.04%) to 54.799%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
core/src/metrics.rs	0	1	0.0%
core/src/monitor.rs	0	2	0.0%
core/src/api.rs	0	4	0.0%

Files with Coverage Reduction	New Missed Lines	%
core/src/api.rs	1	0%
core/src/metrics.rs	1	0%

Totals
Change from base Build 5400335715:	-0.04%
Covered Lines:	2061
Relevant Lines:	3761

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💛 - Coveralls