scenarioDefaultTimeout top-level property
What a scenario that names no Timeout of its own gets.
Null here, so a bare flutter test keeps flutter_test's answer. The
harness sets it at startup, because testWidgets stamps every test with the
binding's ten minutes and a runner that wants its own deadline has no other
way to say so — the metadata it reads back cannot tell a default apart from
an author who wrote ten minutes on purpose.
Implementation
Timeout? scenarioDefaultTimeout;