Fix bug introduced when a handler is not created yet; which is the case when f.e. not debugging with guzzle-debug which will initialize the handler in it's service provider. Use singleton resolving for DrupalJsonApiClient, we don't need to initialize it more than one time.
Fix bug introduced when a handler is not created yet; which is the case when f.e. not debugging with guzzle-debug which will initialize the handler in it's service provider.
Use singleton resolving for DrupalJsonApiClient, we don't need to initialize it more than one time.

Prophets/drupal-jsonapi