Any top-level constant
_Any
const Any
Any takes a key and an arbitrary values and choose the one that fits.
Note that the Any unlike other particular types of Field is not a
subclass of it, but rather an instance of callable class that
is designed to mimic Field
's API.
As Any makes runtime type checking make sure that it is used only where it is necessary, otherwise use one of predefined fields.
Implementation
// ignore:constant_identifier_names
const _Any Any = _Any();