Writing serialized Gutenberg blocks in PHP

Sometimes you want to append to `post_content` in PHP.

You can use the get_comment_delimited_block_content function to serialize Gutenberg syntax in a way that correctly shows as blocks in the editor:

$post_content .= get_comment_delimited_block_content(
    'block_name',
    [
        'attribute' => $value,
    ],
    '<p>' . $content . '</p>'
);