code: function getWithResolvedData(ctx, cur, down) {
      return function(data) {
        return ctx.push(data)._get(cur, down);
      };
    }
docs: Factory function that creates a closure scope around a Thenable-callback.
  Returns a function that can be passed to a Thenable that will resume a
  Context lookup once the Thenable resolves with new data, adding that new
  data to the lookup stack.