toString method
A string representation of this object.
Some classes have a default textual representation,
often paired with a static parse function (like int.parse).
These classes will provide the textual representation as
their string representation.
Other classes have no meaningful textual representation
that a program will care about.
Such classes will typically override toString to provide
useful information when inspecting the object,
mainly for debugging or logging.
Implementation
@override
String toString() => 'ReferenceAnswer[age=$age, asOf=$asOf, from=$from, hit=$hit, key=$key, matched=$matched, refusal=$refusal, score=$score, set_=$set_, stale=$stale, value=$value, verdict=$verdict, version=$version]';