src/Reflection/ReflectionFunctionAbstract.php
public function isVariadic() : bool
    {
        $parameters = $this->getParameters();

        foreach ($parameters as $parameter) {
            if ($parameter->isVariadic()) {
                return true;
            }
        }

        return false;
    }
public function isVariadic() : bool
    {
        $parameters = $this->getParameters();

        foreach ($parameters as $parameter) {
            if ($parameter->isVariadic()) {
                return true;
            }
        }

        return false;
    }
Check if the function has a variadic parameter.