[mkarg]

1 Summary

Issue eclipse-ee4j#5600 reports that NettyConnector does not respect timeouts: a request against a server
that was shut down hangs despite ClientProperties.CONNECT_TIMEOUT being set.

The timeout handling in the current code works: the read timeout is implemented by an
IdleStateHandler in the pipeline (NettyConnector#execute), the IdleStateEvent is handled by
JerseyClientHandler#userEventTriggered, which closes the channel, and
JerseyClientHandler#channelInactive completes the response future with a TimeoutException.
The connect timeout is passed to the Bootstrap via ChannelOption.CONNECT_TIMEOUT_MILLIS.

This PR adds a regression test that verifies ClientProperties.READ_TIMEOUT against a server
that accepts the connection but never sends a response.

2 Verification

All scenarios from eclipse-ee4j#5600 were executed against the current code:

• READ_TIMEOUT against a server that accepts the connection but never responds:
  the request fails with a ProcessingException caused by a TimeoutException within
  the configured read timeout (new test ReadTimeoutRespectedTest, ~2s for a 2s timeout)
• Request against a live server, then shutdown the server, then a subsequent request
  with CONNECT_TIMEOUT=30s: fails immediately with Connection refused, no hang
• CONNECT_TIMEOUT=3s against a non-routable address (dropped SYN, no RST):
  fails with ConnectTimeoutException: connection timed out after 3000 ms after ~3.5s

The existing tests still pass:

mvn -pl :jersey-netty-connector test -Dtest='ReadTimeoutRespectedTest,TimeoutTest,ConnectionExceptionTest'
Tests run: 1, Failures: 0, Errors: 0 -- ReadTimeoutRespectedTest (2.031 s)
Tests run: 5, Failures: 0, Errors: 0 -- TimeoutTest
Tests run: 1, Failures: 0, Errors: 0 -- ConnectionExceptionTest

The issue is no longer reproducible; the reporting user never replied to the reproducer
results in the issue.

Closes eclipse-ee4j#5600