Decrease default timeout values for Tokens and Segments

With the complexity and prevalence of asynchronous code, the Java agent frequently encounters timeouts with the Token and Segment APIs, which belong to the agent's Async API. New Relic Transactions will stay alive until all Tokens and Segments have been ended. In cases where they don't end naturally, they will stay alive until timing out.

The current timeout values for these APIs is far too high:

• token_timeout : default 180 seconds
• segment_timeout : default 600 seconds

Scenarios where throughput is extremely high and Token/Segment timeouts regularly occur can lead to excessive memory consumption that resembles a memory leak (though technically is not a leak).

We should run some analysis and determine more reasonable timeout defaults, which could have a great positive effect on memory consumption.

Questions to answer:

• What are reasonable default timeout values?
• Should decreasing these values be considered a breaking change and require a major release?

Start by analyzing the Token and Segment APIs and their token_timeout and segment_timeout configuration values, using the linked Async API and configuration documentation as context. Determine evidence-based default values and assess whether changing them is a breaking change that requires a major release; done means both questions have a documented decision.