adding comment

Author: camillobruni

tests/run.mjs

@@ -83,6 +83,8 @@ async function testEnd2End() {
     try {
         await driver.get(`http://localhost:${PORT}/index.html?worstCaseCount=2&iterationCount=3`);
         await driver.executeAsyncScript((callback) => {
+            // callback() is explicitly called without the default event
+            // as argument to avoid serialization issues with chromedriver.
             globalThis.addEventListener("JetStreamReady", () => callback());
             // We might not get a chance to install the on-ready listener, thus
             // we also check if the runner is ready synchronously.