Problem: stores map not pre-allocated

[yihuang]

Solution:

• pre-allocate to save some allocation cost

Description

Closes: #XXXX

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Author Checklist

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• included the correct type prefix in the PR title
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[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.