Using Drupal's Entity Definition Update Manager to add bundle support to an existing content entity
On a client project we were using a custom Drupal content entity to model some lightweight reusable content.
The content entity was originally single use and did not support bundles (e.g. node entities have node-type bundles).
As the project evolved, we needed to add bundle support for the custom entity-type, despite it already being in production use.
Read on to find out how we achieved this.
