In our Java app we have what is basically boilerplate S3 V2 code for creating a multipart upload of a file to S3. We absolutely
need the ability to cancel the upload, and recover all resources used by the upload process, INCLUDING the CPU and network
bandwidth. Initially we tried simply cancelling the completionFuture on the FileUpload, but that doesn't work. I can watch the network traffic continue to
send data to S3, until the entire file is uploaded. Cancelling the completionFuture seems to stop S3 from reconstructing
the file, but that's not sufficient. In most cases we need to cancel the upload because we need the network bandwidth
for other things, like streaming video.
I found the function shutdownNow() in the TransferManager class, and that seemed promising, but it looks like it's not
available in the V2 SDK (I found it in the V1 sources).
I've seen a function getSubTransfers() in the V1 MultipleFileUpload class that returns a list of Uploads, and the Upload class
has an abort() function, but again, we need to use V2 for other reasons.
I've also found and implemented code that calls listMultipartUploads, looks for the upload we want to cancel, creates an
abortMultipartUploadRequest, issues it and the threads keep on rolling, and rolling, and rolling....
Is there a "correct" way of terminating a multipart upload, including the threads processing the upload?