dist/index.js
function onupgrade (to) {
    if (transport$$1 && to.name !== transport$$1.name) {
      debug$2('"%s" works - aborting "%s"', to.name, transport$$1.name);
      freezeTransport();
    }
  }
function onupgrade (to) {
    if (transport$$1 && to.name !== transport$$1.name) {
      debug$2('"%s" works - aborting "%s"', to.name, transport$$1.name);
      freezeTransport();
    }
  }
When the socket is upgraded while we're probing