$ composer diagnose
Checking composer.json: OK
Checking platform settings: OK
Checking git settings: OK
Checking http connectivity to packagist: OK
Checking https connectivity to packagist: OK
Checking github.com rate limit: OK
Checking disk free space: OK
Checking pubkeys:
Tags Public Key Fingerprint: 57815B 4E5D42D0 84A14642
Dev Public Key Fingerprint: 4AC457  AD90147D AFE50952
OK
Checking composer version: OK
Composer version: 1.8.3
PHP version: 7.1.5
PHP binary path: C:\wamp64\bin\php\php7.1.5\php.exe

Komputer MINGW64 /c/wamp64/www/notification (master)
$ composer status
^C
Komputer MINGW64 /c/wamp64/www/notification (master)
$ composer require symfony/twig-bundle

{
    "config": {}
}