How to store a Guzzle Stream using Storage::putFile?

I pipe emails to my Laravel app and I get the attachements. I end up with a GuzzleHttp\Psr7\CachingStream / GuzzleHttp\Psr7\Stream to store in AWS.

However, I get the following exception: call_user_func_array() expects parameter 1 to be a valid callback, class 'GuzzleHttp\Psr7\Stream' does not have a method 'hashName'

Here is my method:

    public function setCVAttribute($value) {
        if($value != null) {
            if(isset($this->attributes['cv']) && Storage::exists($this->attributes['cv'])) {
                Storage::delete($this->attributes['cv']);
            }
            $path = Storage::putFile('cvs', $value);
            $this->attributes['cv'] = $path;
        }
    }

Can anyone help me?