Failed to start the session because headers have already been sent

To fix the "headers already sent" issue, I added a check in the BigPipe.php file to make sure the headers hadn’t already been sent before printing the content:

if (!headers_sent()) {
    if ($chunk instanceof HtmlResponse) {
        print $chunk->getContent();
    } else {
        print $chunk;
    }
    flush();
} else {
    // You can handle the situation here if the headers have already been sent
}

I also tried wrapping the code in an output buffer to prevent anything from being sent too early, which helped avoid the error:

ob_start();

// Here’s the code that sends the headers or starts a session
if ($chunk instanceof HtmlResponse) {
    print $chunk->getContent();
} else {
    print $chunk;
}
flush();

ob_end_flush();

How do we set up a view that sends email? Have you searched this issue queue for the same error? In past I think it was because there are PHP files with spaces before the opening tag.