Each FileTarget must first write to a temp file, then when done, copy it out to final dest. This is to avoid Luigi's [atomic writes problem](https://luigi.readthedocs.io/en/stable/luigi_patterns.html#atomic-writes-problem) (i.e. other workers thinking a task is complete when its output is still being written)
Each FileTarget must first write to a temp file, then when done, copy it out to final dest.
This is to avoid Luigi's atomic writes problem
(i.e. other workers thinking a task is complete when its output is still being written)