$params = wp_fusion()->crm->get_params();

$engagement_data = array(
    'engagement'   => array(
        'type' => 'NOTE',
    ),
    'associations' => array(
        'dealIds' => array( $deal_id ),
    ),
    'metadata'     => array(
        'body' => $body,
    ),
);

$params         = wp_fusion()->crm->get_params();
$params['body'] = json_encode( $engagement_data );

$response = wp_remote_post( 'https://api.hubapi.com/engagements/v1/engagements', $params );