Adding rocksdb throttling counters to trace event.

[neethuhaneesha]

cherry-pick #7075
Adding rocksdb throttling counters to trace event.

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• The PR has a description, explaining both the problem and the solution.
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• This change/bugfix is a cherry-pick from the next younger branch (younger release-branch or main if this is the youngest branch)
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[fdb-windows-ci]

Doxense CI Report for Windows 10

• Commit ID: aeab889
• Result: ✔️ SUCCEEDED
• Build Logs (available for 30 days)

[foundationdb-ci]

AWS CodeBuild CI Report for macOS BigSur 11.5.2

• CodeBuild project: foundationdb-pr-macos
• Commit ID: aeab889
• Result: SUCCEEDED
• Error: N/A
• Build Logs (available for 30 days)

[foundationdb-ci]

AWS CodeBuild CI Report for Linux CentOS 7

• CodeBuild project: foundationdb-pr
• Commit ID: abee33d
• Result: SUCCEEDED
• Error: N/A
• Build Logs (available for 30 days)

[foundationdb-ci]

AWS CodeBuild CI Report for Linux CentOS 7

• CodeBuild project: foundationdb-pr
• Commit ID: aeab889
• Result: SUCCEEDED
• Error: N/A
• Build Logs (available for 30 days)

[neethuhaneesha]

Thanks @jzhou77