feat(java): implement connection pooling for AsyncTcpConnection (…

[rythm-sachdeva]

Description

This PR implements connection pooling for the AsyncTcpConnection in the Java SDK, resolving issue #2232.

Previously, the async client used a single connection, which could lead to bottlenecks. This implementation introduces a configurable pool (using Netty's FixedChannelPool) to improve throughput and reliability.

Key Changes

• Integrated Netty's FixedChannelPool into AsyncTcpConnection.
• Added TCPConnectionPoolConfig to allow configuration of:
  • Max connections
  • Max pending acquires
  • Acquire timeout
• Implemented PoolMetrics to track:
  • Active/Idle connections
  • Wait times and errors
• Updated sendAsync to acquire channels from the pool and release them back upon completion (or failure).
• Added logic to handle CompletableFuture cancellation and channel health checks.

Issue Link

Closes #2232

Checklist

• My code follows the code style of this project (Checkstyle passed).
• I have added tests to cover my changes. (Optional: Check if you added tests)

[mmodzelewski]

Hey @rythm-sachdeva, please fix the CI issues and ping me once the PR is ready for review.

[rythm-sachdeva]

Sure @mmodzelewski

[rythm-sachdeva]

Hi @mmodzelewski Can You review it now

[hubcio]

@rythm-sachdeva lints are not passing and PR is not rebased. we will not check it until CI is green.