Log Slow Outgoing HTTP Requests

// Requests slower than this many seconds are logged.
$wpide_http_slow = 1.0;

add_filter( 'pre_http_request', function ( $pre, $args, $url ) {
    $GLOBALS['wpide_http_timers'][ md5( $url ) ] = microtime( true );
    return $pre;
}, 1, 3 );

add_action( 'http_api_debug', function ( $response, $context, $class, $args, $url ) use ( $wpide_http_slow ) {
    $key = md5( $url );

    if ( empty( $GLOBALS['wpide_http_timers'][ $key ] ) ) {
        return;
    }

    $time = microtime( true ) - $GLOBALS['wpide_http_timers'][ $key ];
    unset( $GLOBALS['wpide_http_timers'][ $key ] );

    if ( $time < $wpide_http_slow ) {
        return;
    }

    $parts   = wp_parse_url( $url );
    $clean   = ( isset( $parts['host'] ) ? $parts['host'] : '' ) . ( isset( $parts['path'] ) ? $parts['path'] : '' );
    $where   = is_admin() ? 'admin' : ( wp_doing_cron() ? 'cron' : 'front' );
    $log     = (array) get_option( 'wpide_slow_http', array() );
    $log[]   = array(
        'url'    => $clean,
        'method' => isset( $args['method'] ) ? $args['method'] : 'GET',
        'time'   => round( $time, 2 ),
        'status' => is_wp_error( $response ) ? $response->get_error_message() : wp_remote_retrieve_response_code( $response ),
        'where'  => $where,
        'when'   => time(),
    );

    update_option( 'wpide_slow_http', array_slice( $log, -100 ), false );
}, 10, 5 );

add_action( 'admin_menu', function () {
    add_management_page( 'Slow HTTP Calls', 'Slow HTTP Calls', 'manage_options', 'wpide-slow-http', function () {
        $log = array_reverse( (array) get_option( 'wpide_slow_http', array() ) );

        echo '<div class="wrap"><h1>Slow HTTP Calls</h1><table class="widefat striped"><thead><tr><th>When</th><th>Request</th><th>Time</th><th>Result</th><th>Context</th></tr></thead><tbody>';
        if ( ! $log ) {
            echo '<tr><td colspan="5">No slow requests logged yet.</td></tr>';
        }
        foreach ( $log as $row ) {
            printf( '<tr><td>%s</td><td><code>%s %s</code></td><td>%ss</td><td>%s</td><td>%s</td></tr>', esc_html( human_time_diff( (int) $row['when'] ) . ' ago' ), esc_html( $row['method'] ), esc_html( $row['url'] ), esc_html( $row['time'] ), esc_html( (string) $row['status'] ), esc_html( $row['where'] ) );
        }
        echo '</tbody></table></div>';
    } );
} );