A question that asks the model whether a proposition is true.
Collects the definition of one proposition question. Each call to build returns a new question, and later changes to the builder do not affect questions it already built. A builder is not safe for use from several threads at once.
The text that tells the model what to decide.
The kind of the question, which matches its result type.
The caller-owned name of the question. It is unique within a spec and names the answer in a response.