[Performance] Improve Syslog Input Connection Performance

[kaisecheng]

This plugin creates a new thread to handle a new connection. This is not the best use of the resources, especially when there is a high number of connections, the CPU usage increases significantly.

beats-input uses Netty server to handle connection. Changing thread-based connections to NIO would be the right way to go.

[roaksoax]

There's been recent reports that after upgrading to latest version of Logstash, that CPU usage increases even with the lack of performance improvement on this area.

As part of this, we shoul.d investigate whether this problem is being made worse by Jruby,.

[iamhowardtheduck]

This is affecting one of my customers and we are actively looking for updates. The current suggestion from support is to downgrade and I also discussed migrating to Elastic ingest pipelines since this is just basic syslog ingestion coupled with custom parsing.