Implementation class providing the @tapjs/nock!index.TapNock#nock method on the @tapjs/test!index.Test class.
Lazily attached property, since the teardown() method doesn't exist at construct time, because it's provided by another plugin. While we're at it, save the work of setting up the nock method as well, until it's actually accessed for the first time.
Implementation class providing the @tapjs/nock!index.TapNock#nock method on the @tapjs/test!index.Test class.