How to use map base field definition in a custom content entity form

Question

I have a custom content entity and i'd like to use a map BaseFieldDefinition type to hold an arbitrary number of options.

This is in my custom content entity baseFieldsDefinitions():

$fields['options'] = BaseFieldDefinition::create('integer')
      ->setLabel(t('Task options'))
      ->setDescription(t('The task options.'))
      ->setSettings(array(
           'type' => 'map',
            'default_value' => null
       ));

How do I display this as part of the entity form?

My instinct is that I'd need to create a custom widget, custom formatter and add the following to the base field definition:

->setDisplayOptions('form', array(
         'type' => 'custom_widget',
          'weight' => -6,
  ))

Any direction would be much appreciated.