Notes
- Send synthetics headers even when CAT disabled - The agent now sends synthetics headers whenever they are received from an external request, even if cross-application tracing is disabled. 
- Bugfix for DelayedJob Daemonization - Customers using the delayed_job script that ships with the gem may encounter an IOError with a message indicating the stream was closed. This was due to the agent attempting to write a byte into a Pipe that was closed during the deamonization of the delayed_job script. This issue has been fixed. 
- Collect supportability metrics for public API - The agent now collects Supportability/API/{method} metrics to track usage of all methods in the agent's public API. 
- Collect supportability metrics on - Module#prepend- The agent now collects Supportability/PrependedModules/{Module} metrics for ActiveRecord 4 and 5, ActionController 4 and 5, ActionView 4 and 5, ActiveJob 5, and ActionCable 5. These help track the adoption of the - Module#prependmethod so we can maintain compatibility with newer versions of Ruby and Rails.
- Collect explain plans when using PostGIS ActiveRecord adapter - The agent will now collect slow SQL explain plans, if configured to, on connections using the PostGIS adapter. Thanks Ari Pollak for the contribution! 
- Lazily Intialize New Relic Config - The agent will lazily initialize the New Relic config. This allows the agent to pickup configuration from environment variables set by dotenv and similar tools.