jooby-netty: possible leak in scheduled tasks under HTTP traffic

[NastyaYarotskas]

Bug

jooby-netty shows increasing memory and CPU usage under repeated HTTP traffic.
After traffic stops, usage stays high instead of returning to baseline.

Environment

• Jooby: 4.0.15
• JDK: 21
• Netty server
• Reproducer: https://github.com/NastyaYarotskas/reproduce-jobby-netty-leak

Steps to reproduce

1. mvn clean package
2. ./runJar.bat
3. Send ~500 req/s with any HTTP request for ~30 min
4. Stop traffic and observe metrics

Expected

Memory/CPU should drop close to baseline after traffic stops.

Actual

Memory/CPU remain elevated; object counts keep growing across bursts.

Observations

• scheduledTaskQueue keeps growing
• NettyString / NettyDateService are not fully released

Possible cause

NettyDateService is created per connection and schedules periodic tasks (scheduleAtFixedRate(...)) that appear not to be cancelled on channel close.

[jknack]

fixed in 4.0.17