Type Alias ExtraColumns 

pub type ExtraColumns = HashMap<String, Value>;

Key-value bag for extra columns that hooks can read/write.

On writes, the hook populates values (e.g. "EXPIRES_AT" → "2099-01-01") and the backend persists them to the extra columns declared in schema config. On reads, the backend fills the bag from stored extra column values so the hook can inspect them.

Aliased Type

pub struct ExtraColumns { /* private fields */ }