A message describing a condition that will eventually lead to a persistent store not being loaded. For example being unable to find an appropriate model for a persistent store. Rare, does not occur at all during normal operations.

A message describing a condition that is unusual but does not immediately lead to a problem for the app. For example being unable to load a model from a file on disk. Rare, does not occur at all during normal operations.

A message describing normal progress of the library that may be of interest to an app developer. For example listing all discovered models and their relations. Occurs fairly often during normal operations (<1KiB for a complex migration).

A message describing normal progress of the library that is probably only interesting when attempting to debug the library internals. Occurs often during normal operations.