Provide concrete example of building custom events #640

To help us debug your issue fill in the basic information below using the options provided

Serverless Java Container version: eg. 1.5
v1 (Spring Boot 2) and v2 (Spring Boot 3.x)

Implementations: Jersey / Spring / Spring Boot / Spring Boot 2 / Spark
Spring Boot

Framework version: eg SpringBoot 2.2.6.RELEASE
Spring Boot 2.x and Spring Boot 3.x

Frontend service: REST API / HTTP API / ALB
VPC Lattice

Deployment method: eg SAM, Serverless Framework, Console
N/A

Scenario

Describe what you are trying to accomplish
This is a more general ask related to this issue. The documentation provided here indicates that just four classes need to be implemented to build the custom class. However, pursuant of trying to implement the VPC Lattice event, I discovered that in addition to creating the POJOs for the event model itself, I needed to also implement ExceptionHandler, SecurityContext, SecurityContextWriter. It would helpful to include a practical example of how to create the custom event, outline the minimum and optional attributes for the servlet request, and how to set fields for the response payload.

Expected behavior

Describe how you would expect the application to behave
Ability to simply or at least clear extend the framework with custom event payloads

Actual behavior

Describe what you are seeing instead
Difficulty following the documentation