PHP デバッグ

<?php
$log = array(
    "x1" => "y1",
    "x2" => "y2",
    "x3" => "y3"
);

//バッファ出力開始
ob_start();
//配列をダンプ
var_dump($log);
//バッファの内容を変数に代入
$dump = ob_get_contents();
// バッファ終了
ob_end_clean();
error_log($dump,3,'./dump.txt');

error_log(var_export($log, true), 3, "./export.txt");
error_log(print_r($log, true), 3, "./r.txt");