Check if file is empty

[tiagofilipe12]

While running a task watermill should check if file is empty before executing it. One simple way to do so would be to check if file size is 0.

[thejmazz]

There is code for this but it was toggled off near the end of my GSOC.

This is part of "validators", which can be ran before a task, after a task, and later we should add the ability for users to pass per filetype validators per task, stream validators (i.e. check if each object has required keys), etc

[thejmazz]

We should close this issue once that validation is re-enabled and we have tests for this

[tiagofilipe12]

Since I couldn't replicate this I will close it.