Closed without sending a request; it was probably just an unused speculative preconnection

When a query is closed without sending a request and it was probably just an unused speculative preconnection, it means that the connection was never established with the server. This can happen in scenarios where a web browser or application attempts to establish a connection with a server in anticipation of a potential request, but the request is never actually made.

For example, let’s say a web page contains multiple links to external resources such as images or stylesheets. When the browser parses the HTML and encounters these links, it may try to establish a connection with the server hosting those resources even before the user clicks on those links. This is known as speculative preconnection.

However, if the user closes the webpage or navigates away before actually requesting those resources, the connections that were pre-established will never be utilized. These connections are essentially unused and remain idle.

Here is a simple HTML code snippet that demonstrates a speculative preconnection scenario:

<!DOCTYPE html>
    <html>
      <head>
        <link rel="stylesheet" href="styles.css">
      </head>
      <body>
        <h1>Welcome to My Website</h1>
        <p>Lorem ipsum dolor sit amet...</p>
        <a href="page2.html">Next Page</a>
        <script src="script.js"></script>
      </body>
    </html>
  

In the above example, the browser will try to establish connections with the servers hosting the “styles.css” file and “script.js” file as soon as the HTML is parsed. If the user closes the web page or navigates away before the browser requests those resources, the pre-established connections become closed without sending any actual requests.

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