src/Iadvize/ApiRestClient/Request.php
public function addField($field, $value)
    {
        if (!in_array($field, $this->fields)) {
            $this->fields[$field] = $value;
        }
    }
public function addField($field, $value)
    {
        if (!in_array($field, $this->fields)) {
            $this->fields[$field] = $value;
        }
    }
Add field

@param string $field Field
@param mixed $value Value