CurlRequest result = request.param("key1", "value1").param("key2", "value2");

        assertSame(request, result); // Fluent API
    }

    @Test
    public void testParamWithNullValue() {
        CurlRequest request = new CurlRequest(Method.GET, "https://example.com");

        CurlRequest result = request.param("key", null);