Asset manager properties allow for an event based key-value store under a given namespace. This is currently used, for example, by the workflow service which stores workflow variables passed to workflows as user input to ensure they are available for a new workflow as well.
One problem of these properties is that they are never exposed, making them extremely hard to access for things like a migration from file-based workflow variable storage to asset manager based storage.
This patch aims to provide a basic API to read and write properties. It is especially focused on workflow variables.