LeadImportBulkRequest(Bulk (leads[]))

{
    "source_type": "string",
    "leads": [
        {
            "source_type": "string",
            "fields": [
                {
                    "field_name": "string",
                    "value": "string"
                }
            ],
            "contacts": [
                {
                    "contact_id": 1
                }
            ]
        }
    ]
}