Call Bootstrap.connect() with resolved InetSocketAddress

[Copilot]

Hostname resolution was occurring on Netty event loop threads instead of the calling thread. This mirrors the fix in eclipse-milo/milo#1668.

Changes

• NettyTcpClientTransport: Construct InetSocketAddress before passing to Bootstrap.connect()
• NettyRtuClientTransport: Construct InetSocketAddress before passing to Bootstrap.connect()

Technical Details

Calling Bootstrap.connect(hostname, port) creates an unresolved InetSocketAddress that Netty resolves later on its event loop. Passing a pre-constructed InetSocketAddress(hostname, port) forces immediate DNS resolution on the calling thread.

// Before
bootstrap.connect(config.hostname(), config.port())

// After  
bootstrap.connect(new InetSocketAddress(config.hostname(), config.port()))

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• checkstyle.org
  • Triggering command: /opt/hostedtoolcache/CodeQL/2.23.6/x64/codeql/tools/linux64/java/bin/java /opt/hostedtoolcache/CodeQL/2.23.6/x64/codeql/tools/linux64/java/bin/java -jar /opt/hostedtoolcache/CodeQL/2.23.6/x64/codeql/xml/tools/xml-extractor.jar --fileList=/home/REDACTED/work/modbus/.codeql-scratch/dbs/java/working/files-to-index11882398739134291682.list --sourceArchiveDir=/home/REDACTED/work/modbus/.codeql-scratch/dbs/java/src --outputDir=/home/REDACTED/work/modbus/.codeql-scratch/dbs/java/trap/java (dns block)
• https://api.github.com/repos/eclipse-milo/milo/pulls/1668
  • Triggering command: /usr/bin/curl curl -s REDACTED (http block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

The fix done in this PR to the Milo repository: eclipse-milo/milo#1668

fixes an issues that also likely needs to be fixed here. Find out of the Netty transport connects using the same API that results in an unresolved InetSocketAddress and if so make the same fix here.

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[Copilot]

Pull request overview

This PR fixes a performance issue where hostname resolution was occurring on Netty event loop threads instead of the calling thread. This mirrors the fix from eclipse-milo/milo#1668 and ensures DNS resolution doesn't block event loop threads that should be reserved for I/O operations.

Key Changes:

• Modified both Netty client transport implementations to pre-construct InetSocketAddress objects before passing them to Bootstrap.connect()
• Added java.net.InetSocketAddress import to both affected files

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
modbus-tcp/src/main/java/com/digitalpetri/modbus/tcp/client/NettyTcpClientTransport.java	Updated TCP client transport to resolve hostnames on the calling thread by pre-constructing InetSocketAddress
modbus-tcp/src/main/java/com/digitalpetri/modbus/tcp/client/NettyRtuClientTransport.java	Updated RTU/TCP client transport to resolve hostnames on the calling thread by pre-constructing InetSocketAddress

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