I'd like to propose an improvement of the DevUtils module. Currently, using IDebugBarContributor, it's not possible to collect data during each request and make it available on a DevUtilsPage.
Here's an example: Let's say you wanted to implement a Contributor that shows the number of SQL queries issued during each request in the DebugBar, and a list of detailed SQL queries on the linked DevUtilsPage.
This is currently not possible due to the following reasons:
1. You don't have access to the current RequestData object through the IRequestLogger interface
2. The RequestData class does not allow to store user data (in this case the SQL queries)
Therefore, i'd like to propose a patch that addresses the 2 issues above. This could look something like this: https://github.com/pulse00/wicket/commit/b3c52a777847ac71f86a527710f62d487c2621a3 (note that this is just a draft).