r(_functionObject_, "%GeneratorPrototype%", «[[GeneratorState]], [[GeneratorContext]]» ).
      4. ReturnIfAbrupt(_G_).
      5. Perform GeneratorStart(_G_, |FunctionBody|).
      6. Return Completion{[[type]]: ~return~, [[value]]: _G_, [[target]]: ~empty~}.
    </emu-alg>
  </emu-clause>
</emu-clause>
