title: GCP-Storage: do files appear before upload is complete
body: <p>I want to transfer files into a VM whenever there is a new file added to storage, the problem is that i want the transfer to be done only when the upload is complete </p>
  
  <p><strong>So my question is :</strong> Do files appear even when the upload is still going on ? which means if I build a program that looks for new files every second, would it transfer the files from gcs to VM even if the upload is incomplete or the transfer would start whenever the upload is complete and not while it is uploading ? </p>