Don't record most HTTP request and response headers in the APM, except for the User-Agent, Referer, Save-Data, X-Forwarded-For, Accept-Language, and Content-Type headers. Recording every HTTP header for every request takes up a lot of space and most of them aren't very useful.
Initializers
This directory contains initializers run by Rails during bootup. Initializers are generally used to configure libraries or other global settings during application boot.