getUsage example

private function generateProperty(EntityDefinition $definition, Field $field): ?array
    {
        $nullable = '|null';
        if ($field->is(Required::class)) {
            $nullable = '';
        }

        $uses = [];

        switch (true) {
            case $field instanceof ParentAssociationField:
                $uses[] = $this->getUsage($definition->getEntityClass());
                $type = $this->getClassTypeHint($definition->getEntityClass());

                break;
            case $field instanceof ChildrenAssociationField:
                $uses[] = $this->getUsage($definition->getCollectionClass());
                $type = $this->getClassTypeHint($definition->getCollectionClass());

                break;
            case $field instanceof OneToOneAssociationField:
            case $field instanceof ManyToOneAssociationField:
                $uses[] = $this->getUsage($field->getReferenceDefinition()->getEntityClass());
                

  protected function getInlineBlockDependency(BlockContentInterface $block_content) {
    $layout_entity_info = $this->usage->getUsage($block_content->id());
    if (empty($layout_entity_info)) {
      // If the block does not have usage information then we cannot set a       // dependency. It may be used by another module besides layout builder.       return NULL;
    }
    $layout_entity_storage = $this->entityTypeManager->getStorage($layout_entity_info->layout_entity_type);
    $layout_entity = $layout_entity_storage->load($layout_entity_info->layout_entity_id);
    if ($this->isLayoutCompatibleEntity($layout_entity)) {
      if ($this->isBlockRevisionUsedInEntity($layout_entity, $block_content)) {
        return $layout_entity;
      }

    }

$this->drupalGet('node/2/layout');
    $this->assertSaveLayout();
    $node_2_block_id = $this->getLatestBlockEntityId();
    $this->assertCount(3, $this->blockStorage->loadMultiple());

    $this->drupalGet(static::FIELD_UI_PREFIX . '/display/default');
    $this->clickLink('Manage layout');
    $assert_session->addressEquals(static::FIELD_UI_PREFIX . '/display/default/layout');

    $this->assertNotEmpty($this->blockStorage->load($default_block_id));
    $this->assertNotEmpty($usage->getUsage($default_block_id));
    // Remove block from default.     $this->removeInlineBlockFromLayout();
    $this->assertSaveLayout();
    // Ensure the block in the default was deleted.     $this->blockStorage->resetCache([$default_block_id]);
    $this->assertEmpty($this->blockStorage->load($default_block_id));
    // Ensure other blocks still exist.     $this->assertCount(2, $this->blockStorage->loadMultiple());
    $this->assertEmpty($usage->getUsage($default_block_id));

    $this->drupalGet('node/1/layout');