Avoid calling require('lz4') if it's really not required

[ikkala]

This changes the utlity module to return a function instead of the module directly. This way, caller can control when the module is actually tried to be resolved.

When lz4 disabled, we shouldn't get any error messages / warnings to console.

[Copilot]

Pull request overview

This PR modifies the LZ4 module loading strategy to use lazy initialization instead of immediate evaluation. The lz4.ts utility now exports a getter function rather than directly exporting the module, preventing require('lz4') from being called until the module is actually needed. This eliminates console warnings when LZ4 compression is disabled.

Key Changes:

• Converted the LZ4 module export from direct module resolution to a lazy-loading function pattern
• Updated all call sites to invoke the getter function instead of directly accessing the module
• Added memoization to cache the resolution result (including failures) to avoid repeated resolution attempts

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
lib/utils/lz4.ts	Changed from immediate module resolution to lazy-loading with memoization via getResolvedModule() function
lib/result/CloudFetchResultHandler.ts	Updated to call LZ4() function instead of accessing LZ4 directly in compression checks and decode operations
lib/result/ArrowResultHandler.ts	Updated to call LZ4() function instead of accessing LZ4 directly in compression checks and decode operations
lib/DBSQLSession.ts	Updated to call LZ4() function in the LZ4 capability check

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[shivam2680]

Thanks for the contribution!
Can you add a test suite for verifying the lazy loading behavior?
Also, please mention testing steps in the PR description

[samikshya-db]

Thanks for this fix, Ikkala.
+1 to @shivam2680 's comments

Earlier we had fixed LZ4 module loading for azure functions in #298 - this handled cases when lz4 wasn't available. But this lazy loading is a neat addition to it.

[ikkala]

Thanks for the contribution! Can you add a test suite for verifying the lazy loading behavior?

Added unit tests for the lz4.ts module now.

Also, please mention testing steps in the PR description

This is a bit hard because I don't have use cases where I need lz4. 🤔 Aren't the e2e tests (that I cannot run) verifying the functionality with real lz4?