Updated CompositeByteBuf to be responsible for retaining its ByteBufs

[rozza]

• Updated NettyByteBuf so that it does its own reference counting as the internals of Netty can also retain and release the netty ByteBuf implementation.
• Updated CommandMessage as CompositeByteBuf handles the releasing of its ByteBufs
• Migrated CompositeByteBufSpecification to JUnit 5 and added extra test cases with mixed ByteBuf types not just NIO ones.
• Added recording to CommandHelperSpecification as this caught the initial use of Netty doing its own accounting on its ByteBuf implementations.

JAVA-5982

[Copilot]

Pull Request Overview

This PR updates CompositeByteBuf to take responsibility for managing the reference counting lifecycle of its constituent ByteBuf components, rather than relying on external callers to handle this.

• Updated NettyByteBuf to maintain its own reference count separate from the underlying Netty buffer
• Modified CompositeByteBuf to retain/release component buffers during its own lifecycle management
• Migrated test suite from Groovy/Spock to JUnit 5 with enhanced coverage for mixed buffer types

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
CompositeByteBufTest.java	New JUnit 5 test suite with parameterized tests for ByteBufNIO, NettyByteBuf, and mixed buffer scenarios
CompositeByteBufSpecification.groovy	Removed legacy Groovy/Spock test file being replaced by JUnit 5 version
CommandHelperSpecification.groovy	Added recording configuration to enable proper implementation logging
NettyByteBuf.java	Implemented independent reference counting with AtomicInteger to track buffer lifecycle
CompositeByteBuf.java	Updated to retain/release component buffers and duplicate them properly in copy constructor
CommandMessage.java	Simplified buffer management by removing manual release of byte buffers

Comments suppressed due to low confidence (2)

driver-core/src/test/unit/com/mongodb/internal/connection/CompositeByteBufTest.java:1

• The comment in line 246 says 'accross' but should be 'across'.

/*

driver-core/src/test/unit/com/mongodb/internal/connection/CompositeByteBufTest.java:1

• The comment in line 280 says 'accross' but should be 'across'.

/*

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[codeowners-service-app]

Assigned stIncMale for team dbx-java because nhachicha is out of office.

[stIncMale]

I am still reviewing the PR. Despite the changes in the PR being deceivingly small, they should not be taken lightly.

The way reference counting is done in our codebase is notoriously bad, and caused many difficulties maintaining the codebase in the past. The main reason is, of course, the lack of the language mechanisms in Java that would have allowed us to implement reference-counting in a robust way (Rust with its ownership, ownership transfer and borrowing allows for robust reference counting).