How can logging be implemented in PHP to track the progress of file downloads and identify potential issues?

To track the progress of file downloads and identify potential issues in PHP, logging can be implemented using the error_log() function. By logging messages at different stages of the download process, developers can monitor the progress and troubleshoot any issues that may arise.

// Start of file download
error_log("File download started.");

// Code to download the file

// Check for errors during file download
if ($error_occurred) {
    error_log("Error occurred during file download: " . $error_message);
} else {
    error_log("File download completed successfully.");
}