run method
override
Implements the business logic as a pipeline of steps.
Structure run as a chain of Result.andThen calls: early returns (validations) at the top, the happy path last. Each private method carries a single responsibility and an explicit return type:
@override
Result<User> run() =>
_requireName()
.andThen((_) => _requireEmail())
.andThen((_) => _persistUser());
The first failure in the chain short-circuits all remaining steps.
Implementation
@override
Result<Value> run() => _result;