Error / Exception handling for fileWriteStreamHandler from form.parse

[cubesnyc]

I am passing a fileWriteStreamHandler function to handle uploads to s3. After s3 finishes uploading it runs a callback that notifies the user of any errors. Raising an exception/error within this callback seems to fall outside of the scope of form.parse and therefor the error does not present itself within the file.parse callback. It also does not trigger the error event. How are these errors supposed to be handled within the same scope as file.parse?