Canceling/aborting streams

[vincaslt]

Currently the transform stream reads the file streams in a loop while(true), and pipes the data to the transform stream controller as an output. There are two issues:

1. If a file stream was aborted the error is thrown, but the transform stream doesn't get canceled.
2. If the transform stream stream writer gets aborted, the cancelation does not get piped through to another stream.

[bencmbrook]

Hey @vincaslt do you have a test case for this? Started crafting some here #82

[eligrey]

I think we should improve support for AbortController to better fix this. @bencmbrook I'll have a look at this & review your PR today

[rowanG077]

Would really like to have this. I upload zip files to and when the request files there is no way to signal to the zip transformer to stop. It just throws an error somewhere where I can't catch it.