Slow performance in dev mode since "Use VarDumper in the profiler" #19978
Description
Since 41a7649 forms are very slow in dev mode.
Example: Symfony-Demo, PostType (/de/admin/post/1/edit), added these two fields:
$builder
// ...
->add('country', CountryType::class, [
'mapped' => false,
])
->add('choice', ChoiceType::class, [
'mapped' => false,
'choices' => range(1, 10),
'expanded' => true,
'multiple' => true,
])Blackfire comparison (from commit before 41a7649 to current master): +645%, 227 ms → 1.69 s
In a real-world form in a project it is: 180 ms → 4.2 s
ping @wouterj