uploadable with embedded

Foo.php

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\HttpFoundation\File\File;
use Symfony\Component\HttpFoundation\File\UploadedFile;
use Vich\UploaderBundle\Mapping\Annotation as Vich;

/**
 * @ORM\Embeddable
 * @Vich\Uploadable
 */
class Foo
{
    /**
     * @Vich\UploadableField(mapping="image", fileNameProperty="imageName")
     *
     * @var File
     */
    private $imageFile;

    /**
     * @ORM\Column()
     *
     * @var string
     */
    private $imageName;

    /**
     * @var \DateTime
     *
     * @ORM\Column(name="updated", type="datetime", nullable=true)
     */
    private $updated;

    /**
     * If manually uploading a file (i.e. not using Symfony Form) ensure an instance
     * of 'UploadedFile' is injected into this setter to trigger the  update. If this
     * bundle's configuration parameter 'inject_on_load' is set to 'true' this setter
     * must be able to accept an instance of 'File' as the bundle will inject one here
     * during Doctrine hydration.
     *
     * @param File $image
     */
    public function setImageFile(File $image = null)
    {
        $this->imageFile = $image;
        if ($image instanceof UploadedFile) {
            // It is required that at least one field changes if you are using doctrine
            // otherwise the event listeners won't be called and the file is lost
            $this->updated = new \DateTimeImmutable();
        }
    }

    /**
     * @return File|null
     */
    public function getImageFile()
    {
        return $this->imageFile;
    }

    /**
     * @param string $imageName
     *
     */
    public function setImageName($imageName)
    {
        $this->imageName = $imageName;
    }

    /**
     * @return string|null
     */
    public function getImageName()
    {
        return $this->imageName;
    }
}

User.php

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\HttpFoundation\File\File;
use Vich\UploaderBundle\Mapping\Annotation as Vich;

/**
 * User
 *
 * @ORM\Table(name="user")
 * @ORM\Entity(repositoryClass="AppBundle\Repository\UserRepository")
 * @Vich\Uploadable
 */
class User
{
    /**
     * @var int
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @var string
     *
     * @ORM\Column(name="name", type="string", length=255)
     */
    private $name;

    /**
     * @var Foo
     *
     * @ORM\Embedded(class="AppBundle\Entity\Foo")
     */
    private $foo;

    /**
     * Get id
     *
     * @return int
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * @param string $name
     */
    public function setName($name)
    {
        $this->name = $name;
    }

    /**
     * @return string
     */
    public function getName()
    {
        return $this->name;
    }

    /**
     * @param Foo $foo
     */
    public function setFoo(Foo $foo)
    {
        $this->foo = $foo;
    }

    /**
     * @return Foo
     */
    public function getFoo()
    {
        return $this->foo;
    }

    /**
     * @param string $imageName
     *
     */
    public function setImageName($imageName)
    {
        $this->foo->setImageName($imageName);
    }

    /**
     * @return string|null
     */
    public function getImageName()
    {
        return $this->foo->getImageName();
    }

    /**
     * @param File $image
     */
    public function setImageFile(File $image = null)
    {
        $this->foo->setImageFile($image);
    }

    /**
     * @return File|null
     */
    public function getImageFile()
    {
        return $this->foo->getImageFile();
    }
}

This example, doesn't work at all.