Zend\Diactoros\Stream::read PHP Method

    public function read($length)
    {
        if (!$this->resource) {
            throw new RuntimeException('No resource available; cannot read');
        }
        if (!$this->isReadable()) {
            throw new RuntimeException('Stream is not readable');
        }
        $result = fread($this->resource, $length);
        if (false === $result) {
            throw new RuntimeException('Error reading stream');
        }
        return $result;
    }