Describes an atomic change with metadata and typed parameters.
Polymorphic payload for the specific change.
Epoch millis when the change was created.
Target field id.
Target field identifier.
Layout position id for the field instance.
File id containing the page.
Document id.
External document identifier.
Page id containing the target field.
SDK version string producing the change.
Change target identifier used by handlers.
Schema version for the change envelope.