protected static function getLine(StreamInterface $stream)
    {
        $line    = '';
        $crFound = false;
        while (! $stream->eof()) {
            $char = $stream->read(1);

            if ($crFound && $char === self::LF) {
                $crFound = false;
                break;
            }

            // CR NOT followed by LF
            if ($crFound && $char !== self::LF) {
                throw new UnexpectedValueException('Unexpected carriage return detected');
            }

            // LF in isolation
            if (! $crFound && $char === self::LF) {
                throw new UnexpectedValueException('Unexpected line feed detected');
            }

            // CR found; do not append
            if ($char === self::CR) {
                $crFound = true;
                continue;
            }

            // Any other character: append
            $line .= $char;
        }

        // CR found at end of stream
        if ($crFound) {
            throw new UnexpectedValueException("Unexpected end of headers");
        }

        return $line;
    }