Doesn't display 'headline' for the Blog Posting type?! about json-ld HOT 2 CLOSED

$post_title = 'Test post title';

$JSONsructuredData = \JsonLd\Context::create('blog_posting', [
    'name'             => $post_title,
    'headline'         => $post_title,
    'datePublished'    => '2017-06-09T12:10:49+03:00',
    'dateModified'     => '2017-06-09T12:10:49+03:00',
    'image'            => [
        'type' => 'ImageObject',
        'url'  => 'http://example.com/logo/imge.png',
        'width'  => '850',
        'height' => '350'
    ],
    'publisher'        => [
        'type' => 'Organization',
        'name' => 'SomeBlogSite',
        'logo' => [
            'type'   => 'ImageObject',
            'url'    => 'http://example.com/logo/imge.png',
            'width'  => '600',
            'height' => '150'
        ],
    ],
    'mainEntityOfPage' => [
        'type' => 'WebPage',
        'id'   => 'http://example.com/lobby/slug',
    ],
    'author'           => [
        'type' => 'Person',
        'name' => 'Person name',
    ],

]);

echo $JSONsructuredData;

<script type="application/ld+json">{"@context":"http:\/\/schema.org","@type":"BlogPosting","name":"Test post title","image":{"@type":"ImageObject","url":"http:\/\/example.com\/logo\/imge.png","height":"350","width":"850"},"publisher":{"@type":"Organization","name":"SomeBlogSite",
"logo":{"@type":"ImageObject","url":"http:\/\/example.com\/logo\/imge.png","height":"150","width":"600"}},"dateModified":"2017-06-09T12:10:49+03:00","datePublished":"2017-06-09T12:10:49+03:00","author":{"@type":"Person","name":"Person name"},
"mainEntityOfPage":{"@type":"WebPage"},"headline":"Test post title"}</script>