a == `${worker_2_name}-done`) {
        resolve();
      } else if(e.data == "fail") {
        reject("One opaque origin received a message from the other");
      } else {
        reject("An unexpected error occurred");
      }
    };

    const worker_script = data_url_worker_src(channel_name, worker_2_name);
    const worker1 = new SharedWorker(worker_script, worker_1_name);
    worker1.port.addEventListener("message", handler);
    worker1.port.start();
    worker1.port.postMessage("go!");
    });
}, "B