Using `wp_debug_backtrace_summary()` to only filter something when called from a particular function or method

filter.php

/*
Here we're filtering the site_url() and get_site_url() functions which are called dozens and dozens of times during a request. 
In this case we only want to modify $url if the filter was called from a particular PHP class (rtCamp\WP\Nginx\Helper)
*/
add_filter( 'site_url', function( $url = '' ) {
    $backtrace = wp_debug_backtrace_summary();
    if ( stripos( $backtrace, 'rtCamp\WP\Nginx\Helper' ) ) {
        $url = str_replace( 'https://', 'http://', $url );
    }
    return $url;
});