_constructorBuilder = typeBuilder.defineConstructor(
Modifier.PUBLIC,
Type.list(closureType)
);
final CodeGenerator ctor = _constructorBuilder.getCodeGenerator();
ctor.emitThis();
ctor.call(Types.Object.getConstructors().get(0));
ctor.emitThis();
ctor.emitLoadArgument(0);
ctor.putField(_closureField);
ctor.emitReturn();
}