The code below presents: ($environment, $response)

// ZEND_BEGIN_ARG_INFO_EX(name, _unused, return_reference, required_num_args)
ZEND_BEGIN_ARG_INFO_EX(arginfo_middleware_call, 0, 0, 2)
    ZEND_ARG_INFO(0, environment)
    ZEND_ARG_INFO(0, response)
ZEND_END_ARG_INFO()

The code below presents: (array & $environment, array $response)

ZEND_BEGIN_ARG_INFO_EX(arginfo_middleware_call, 0, 0, 2)
    // ZEND_ARG_ARRAY_INFO(pass_by_ref, name, allow_null)
    ZEND_ARG_ARRAY_INFO(1, environment, 0)
    ZEND_ARG_ARRAY_INFO(0, response, 0)
ZEND_END_ARG_INFO()